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Dynamic logic (modal logic)

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10145:, another variant of modal logic sharing many common features with dynamic logic, differs from all of the above-mentioned logics by being what Pnueli has characterized as an "endogenous" logic, the others being "exogenous" logics. By this Pnueli meant that temporal logic assertions are interpreted within a universal behavioral framework in which a single global situation changes with the passage of time, whereas the assertions of the other logics are made externally to the multiple actions about which they speak. The advantage of the endogenous approach is that it makes no fundamental assumptions about what causes what as the environment changes with time. Instead a temporal logic formula can talk about two unrelated parts of a system, which because they are unrelated tacitly evolve in parallel. In effect ordinary logical conjunction of temporal assertions is the concurrent composition operator of temporal logic. The simplicity of this approach to concurrency has resulted in temporal logic being the modal logic of choice for reasoning about concurrent systems with its aspects of synchronization, interference, independence, 9557:
formalize the intuitive notions of truth and validity, which in turn permit the notions of soundness and completeness to be defined for axiom systems. An inference rule is sound when validity of its premises implies validity of its conclusion. An axiom system is sound when all its axioms are valid and its inference rules are sound. An axiom system is complete when every valid formula is derivable as a theorem of that system. These concepts apply to all
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suffice also for dynamic logic as the only primitive rules it needs, as noted above. However, as usual in logic, many more rules can be derived from these with the help of the axioms. An example instance of such a derived rule in dynamic logic is that if kicking a broken TV once can't possibly fix
10136:
Hoare logic, algorithmic logic, weakest preconditions, and dynamic logic are all well suited to discourse and reasoning about sequential behavior. Extending these logics to concurrent behavior however has proved problematic. There are various approaches but all of them lack the elegance of the
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semantics or Kripke structures. This semantics carries over naturally to dynamic logic by interpreting worlds as states of a computer in the application to program verification, or states of our environment in applications to linguistics, AI, etc. One role for possible world semantics is to
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who showed that PDL was decidable in deterministic exponential time. In 1977, Krister Segerberg proposed a complete axiomatization of PDL, namely any complete axiomatization of modal logic K together with axioms A1–A6 as given above. Completeness proofs for Segerberg's axioms were found by
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means that if the TV is broken, then after kicking it zero or more times it will still be broken. For if not, then after the second-to-last kick the TV would be in a state where kicking it once more would fix it, which the premise claims can never happen under any circumstances.
10124:, weakest liberal precondition. Those logics however made no connection with either modal logic, Kripke semantics, regular expressions, or the calculus of binary relations. Dynamic logic therefore can be viewed as a refinement of algorithmic logic and 2796: 2731: 2949: 2865: 8040: 7519: 7395: 5040:
is an expression built from constants and variables with whatever operations are provided by the language, such as addition and multiplication. The Hoare axiom for assignment is not given as a single axiom but rather as an axiom schema.
9848:. PDL blends the ideas behind propositional logic and dynamic logic by adding actions while omitting data; hence the terms of PDL are actions and propositions. The TV example above is expressed in PDL whereas the next example involving 7680: 3320:
Box and diamond are entirely symmetric with regard to which one takes as primitive. An alternative axiomatization would have been to take the theorems T1–T6 as axioms, from which we could then have derived A1–A6 as theorems.
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however must be true. But this could happen in any situation where the TV is broken but can be revived with two kicks. The implication fails (is not valid) because it only requires that
2623: 10315:, "Dynamic Logic", In D. Gabbay and F. Guenthner, editors, Handbook of Philosophical Logic, volume II: Extensions of Classical Logic, chapter 10, pages 497-604. Reidel, Dordrecht, 1984. 4621: 377: 9573:
has two types of terms, respectively assertions and data. As can be seen from the examples above, dynamic logic adds a third type of term denoting actions. The dynamic logic assertion
8725: 3468:. However the dynamic nature of dynamic logic moves this distinction out of the realm of abstract axiomatics into the common-sense experience of situations in flux. The inference rule 4307: 1944: 7207: 4234: 3957: 9085: 8490: 1794: 1660: 736: 4807: 3021: 582: 8917: 8667: 1197: 7083: 8241:
without impacting any of this, the other direction being provable from A5, from which we see that if the antecedent of A6 does happen to be false somewhere, then the consequent
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Dynamic logic permits compound actions built up from smaller actions. While the basic control operators of any programming language could be used for this purpose,
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is not a natural number, then the antecedent is false and so A6 remains true regardless of the truth of the consequent. We could strengthen A6 to an equivalence
10325:, and Jerzy Tiuryn, "Dynamic Logic", In D. Gabbay and F. Guenthner, editors, Handbook of Philosophical Logic, volume 4: pages 99-217. Kluwer, 2nd edition, 2002. 9477: 9457: 7579: 286: 138: 10128:
that connects them up to the axiomatics and Kripke semantics of modal logic as well as to the calculi of binary relations and regular expressions.
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at the end blocks the performer from terminating the iteration prematurely, but as soon as it becomes false, further iterations of the body
6050: 10306: 6691: 10178: 8552: 2539: 1398: 885: 833: 4812: 8500: 5476:. Such an axiom schema allows infinitely many axioms having a common form to be written as a finite expression connoting that form. 8831: 9482: 9197: 3324:
The difference between implication and inference is the same in dynamic logic as in any other logic: whereas the implication
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is derived from first-order logic by omitting data terms and reasons only about abstract propositions, which may be simple
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is in first-order dynamic logic. PDL is to (first-order) dynamic logic as propositional logic is to first-order logic.
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These operators can be axiomatized in dynamic logic as follows, taking as already given a suitable axiomatization of
10087: 8410: 1801: 1667: 10016: 10125: 2594: 4553: 10283: 10253: 8694: 4239: 1870: 7169: 4178: 3901: 9058: 8464: 1736: 1628: 710: 10377: 4784: 2998: 559: 342: 32: 8889: 8639: 1170: 10146: 7012: 3745: 151: 2791:{\displaystyle \langle a\mathbin {;} b\rangle p\leftrightarrow \langle a\rangle \langle b\rangle p\,\!} 268:(and, or, and not). The action logic is expressive enough to encode programs. For an arbitrary program 100:
which states that if the ground is currently dry and it rains, then afterwards the ground will be wet.
10183: 2726:{\displaystyle \langle a\cup b\rangle p\leftrightarrow \langle a\rangle p\lor \langle b\rangle p\,\!} 188: 7132: 10351: 9886: 9765: 9576: 9383: 9320: 7688: 5604: 5284: 3471: 3399: 2944:{\displaystyle \langle a*\rangle p\to p\lor \langle a*\rangle (\neg p\land \langle a\rangle p)\,\!} 1479: 7865: 6947: 6882: 6630: 6270: 5919: 5187: 5112: 959: 937: 9933: 9737: 9022: 8972: 8922: 8730: 5863: 5638: 5555: 2860:{\displaystyle \langle a*\rangle p\leftrightarrow p\lor \langle a\rangle \langle a*\rangle p\,\!} 1036: 399: 10245: 10239: 9967: 9851: 9703: 9544:. Hence we must either reject Dijkstra's argument or hold that the * operator is not effective. 9459:
to an arbitrary positive integer. However, in dynamic logic with assignment and the * operator,
8035:{\displaystyle (\Phi (n)\land \forall i(\Phi (n+i)\to \Phi (n+i+1)))\to \forall i\Phi (n+i)\,\!} 7514:{\displaystyle (\Phi (n)\land \forall i(\Phi (n+i)\to \Phi (n+i+1)))\to \forall i\Phi (n+i)\,\!} 5972: 4907: 4714: 4513: 4476: 4349: 4312: 4134: 4070: 3999: 3962: 3655: 3574: 3327: 1559: 1508: 464: 9822: 7762: 5891: 5262: 5218: 5143: 2495: 317: 9408: 7735: 7390:{\displaystyle (\Phi (n)\land \forall i(\Phi (n+i)\to \Phi (n+i)))\to \forall i\Phi (n+i)\,\!} 4971: 4107: 1536: 1456: 1359: 1250: 294: 10270: 9907: 9653: 8115: 6627:
One way of dealing with the opacity of modalities is to eliminate them. To this end, expand
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in 1974 in notes for a class on program verification as an approach to assigning meaning to
9405:. That is, first-order logic can be understood as the dynamic logic of programs of the form 8376: 8325: 8278: 419: 265: 10367: 10056: 9681: 9631: 9260: 9238: 9175: 9153: 9112: 9090: 9000: 8950: 8802: 8780: 8758: 8672: 8617: 8354: 8303: 8256: 8143: 8093: 8067: 8045: 7896: 7843: 7813: 7791: 7713: 7549: 7527: 7110: 7088: 6860: 6605: 6583: 6561: 6499: 6477: 6455: 6433: 6411: 6389: 6323: 6301: 6241: 6219: 6028: 6006: 5950: 5897: 5841: 5819: 5797: 5775: 5753: 5673: 5309: 5240: 5165: 5021: 4999: 4941: 4885: 4692: 4670: 4648: 4626: 4445: 4411: 4389: 4039: 3879: 3857: 3818: 3714: 3692: 3633: 3611: 3552: 3530: 3508: 3449: 3427: 3377: 3355: 3298: 3276: 3254: 3232: 3210: 3188: 3166: 3138: 3116: 3094: 3072: 3050: 3028: 2509: 2475: 2453: 2431: 2409: 2387: 2365: 2281: 2259: 2237: 2215: 2193: 2171: 2147: 2125: 2103: 2081: 2059: 2037: 2013: 1977: 1955: 1595: 1329: 1303: 1281: 1228: 1206: 1148: 1126: 1014: 992: 807: 785: 763: 741: 688: 666: 644: 622: 591: 509: 487: 442: 9282: 7675:{\displaystyle (\Phi (0)\land \forall i(\Phi (i)\to \Phi (i+1)))\to \forall i\Phi (i)\,\!} 7397:. The remaining modality can now be eliminated with one more use of Hoare's axiom to give 7212: 6521: 6349: 5816:
is 8 to begin with, or 6.5, whence this proposition is not a theorem of dynamic logic. If
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is a natural number, then the antecedent of the main implication of A6 holds, but then
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for the proposition that the TV is broken, dynamic logic expresses this inference as
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of programs, dynamic logic has been applied to describe complex behaviors arising in
10214: 6047:. The first two of these three instantiations are straightforward, converting A6 to 4104:
means that if the TV is broken, then after kicking it once it will still be broken.
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is that it is guaranteed that after kicking the TV, it is broken. Hence the premise
9558: 6343: 585: 44: 10010: 9436: 7810:. The importance of keeping this typing information straight becomes apparent if 2588:
permits the derivation of the following six theorems corresponding to the above:
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is possibly the case. Dynamic logic extends this by associating to every action
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Propositional dynamic logic, or PDL, was derived from dynamic logic in 1977 by
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claimed to show the impossibility of a program that sets the value of variable
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encodes the correctness of the program, making dynamic logic more general than
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of modal logic in the case when a modality can interfere with a substitution.
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denotes the action of kicking the TV zero or more times. Hence the conclusion
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Fischer and Ladner showed in their 1977 paper that PDL satisfiability was of
7840:, for any of which A6 is perfectly valid as an axiom. As a case in point, if 4510:
hold now, whereas the inference succeeds (is sound) because it requires that
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is true the performer of the action can only take the left branch, and when
8042:, is just as valid, that is, true in every state regardless of the value of 10335: 10322: 10305:, "Semantical Considerations on Floyd-Hoare Logic", Proc. 17th Annual IEEE 10205: 9911: 9479:
can be set to an arbitrary positive integer with the dynamic logic program
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is at most 7 to begin with, that is, it is just a roundabout way of saying
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are blocked and the performer then has no choice but to exit via the test
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or atoms or compound propositions built with such logical connectives as
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is of type integer however, then this proposition is true if and only if
1392: 410: 391: 380: 264:(doing one action zero or more times). The proposition language supports 90:{\displaystyle {\text{The ground is dry}}\to {\text{The ground is wet}},} 40: 7524:
With the opaque modalities now out of the way, we can safely substitute
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For the subject in digital electronics also known as clocked logic, see
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after that performance entails its truth after one more performance of
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including such axioms for modal operators as the above-mentioned axiom
395: 28: 6209:{\displaystyle (\Phi (n)\land (\Phi (n)\to \Phi (n)))\to \Phi (n)\,\!} 2953:
T1 asserts the impossibility of bringing anything about by performing
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acts as the identity function on propositions, that is, it transforms
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in its own right. The system parallels Andrzej Salwicki's system of
6850:{\displaystyle \Phi (n)\land \Phi (n)\land \Phi (n)\land \ldots \,\!} 3854:
it, then repeatedly kicking it can't possibly fix it either. Writing
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have the same meaning. Hence the above proposition is equivalent to
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must be greater or equal to 4. In the case of deterministic actions
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at the present moment is no guarantee of its truth after performing
10150: 9890: 2302:
A5 is the evident result of applying A2, A3 and A4 to the equation
8607:{\displaystyle (p?\mathbin {;} a)\cup (\neg p?\mathbin {;} b)\,\!} 6496:
will result in its executing in a different environment. However,
10278:. Warszawa & Boston: PWN & D. Reidel Publ. p. 372. 9894: 2581:{\displaystyle p\leftrightarrow \neg \langle a\rangle \neg p\,\!} 1440:{\displaystyle p\leftrightarrow \neg \langle a\rangle \neg p\,\!} 1326:
does nothing and does not terminate, whereas the constant action
927:{\displaystyle \langle a\rangle p\leftrightarrow \neg \neg p\,\!} 875:{\displaystyle p\leftrightarrow \neg \langle a\rangle \neg p\,\!} 7710:
should be understood as ranging over the natural numbers, where
4875:{\displaystyle (x\geq 3)\to \langle x:=x+1\rangle (x\geq 4)\,\!} 10208:, and Jerzy Tiuryn, "Dynamic Logic". MIT Press, 2000 (450 pp). 8536:{\displaystyle \langle p?\rangle q\leftrightarrow p\land q\,\!} 8351:, changing nothing while allowing the action to move on. When 5894:
can be obtained as the instance of A6 in which the proposition
7209:. This whole reduction should be applied to both instances of 6518:
itself is not a rigid designator with respect to the modality
8879:{\displaystyle ({p?\mathbin {;} a)*}\mathbin {;} \neg p?\,\!} 7573: 6386:, meaning that it is the same proposition after incrementing 24: 7918:, then axiom A6 after the first two substitutions, that is, 4309:
is not valid because we can easily find situations in which
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of A7 allows us to calculate mechanically that the example
2004:
abstracts the essence of the action of hell freezing over.)
9537:{\displaystyle (x\mathbin {:=} 0)\mathbin {;} (x:=x+1){*}} 8140:
is also a natural number so the consequent also holds. If
3505:, for example, is sound because its premise asserts that 989:
operators are a good match to modal logic. Given actions
934:, analogously to the relationship between the universal ( 10013:'s notion of weakest-precondition predicate transformer 9228:{\displaystyle \langle x\mathbin {:=} {?}\rangle p\,\!} 5794:
equal to 7. This of course is not always true, e.g. if
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An example illustrating assignment in combination with
2657:{\displaystyle \langle 1\rangle p\leftrightarrow p\,\!} 9373:{\displaystyle \langle x\mathbin {:=} {?}\rangle \,\!} 9317:
thus has the same meaning as the universal quantifier
9050: 5545:{\displaystyle (x\geq 4)\leftrightarrow x+1\geq 4\,\!} 1300:
zero or more times, sequentially. The constant action
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Modal logic is most commonly interpreted in terms of
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An example of a valid implication is the proposition
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similarly corresponds to the existential quantifier
8234:{\displaystyle p\land (p\to p)\leftrightarrow p\,\!} 5750:. This asserts that it is possible, by incrementing 5396:{\displaystyle (x=y^{2})\leftrightarrow e=y^{2}\,\!} 5100:{\displaystyle \Phi (x)\leftrightarrow \Phi (e)\,\!} 50:
A simple example of a statement in dynamic logic is
103:The syntax of dynamic logic contains a language of 10116: 10076: 10045: 9993: 9956: 9897:in the worst case. This gap was closed in 1978 by 9874: 9809: 9754: 9726: 9692: 9670: 9642: 9620: 9536: 9471: 9451: 9425: 9397: 9372: 9334: 9309: 9271: 9249: 9227: 9186: 9164: 9142: 9101: 9079: 9039: 9011: 8989: 8961: 8939: 8911: 8878: 8813: 8791: 8769: 8747: 8719: 8683: 8661: 8628: 8606: 8535: 8484: 8451: 8390: 8365: 8339: 8314: 8292: 8267: 8233: 8154: 8132: 8104: 8078: 8056: 8034: 7907: 7885: 7854: 7824: 7802: 7780: 7751: 7724: 7702: 7674: 7560: 7538: 7513: 7389: 7250: 7201: 7158: 7121: 7099: 7077: 7001: 6936: 6871: 6849: 6680: 6616: 6594: 6580:, it denotes 4 after. So we can't just substitute 6572: 6550: 6510: 6488: 6466: 6444: 6422: 6400: 6378: 6334: 6312: 6290: 6252: 6230: 6208: 6039: 6017: 5995: 5961: 5939: 5908: 5880: 5852: 5830: 5808: 5786: 5764: 5742: 5684: 5655: 5627: 5601:encountered a few paragraphs ago is equivalent to 5593: 5544: 5468: 5395: 5320: 5298: 5273: 5251: 5229: 5207: 5176: 5154: 5132: 5099: 5032: 5010: 4988: 4952: 4930: 4896: 4874: 4801: 4773: 4737: 4703: 4681: 4659: 4645:is greater or equal to 3, then after incrementing 4637: 4615: 4547:hold in all situations, not just the present one. 4539: 4502: 4465: 4434: 4400: 4378: 4338: 4301: 4228: 4163: 4123: 4096: 4059: 4028: 3988: 3951: 3890: 3868: 3829: 3807: 3734: 3703: 3681: 3644: 3622: 3600: 3563: 3541: 3519: 3497: 3460: 3438: 3416: 3388: 3366: 3344: 3309: 3287: 3265: 3243: 3221: 3199: 3177: 3149: 3127: 3105: 3083: 3061: 3039: 3015: 2987: 2943: 2859: 2790: 2725: 2656: 2617: 2580: 2520: 2486: 2464: 2442: 2420: 2398: 2376: 2349:{\displaystyle a{*}=1\cup a{\mathbin {;}}a{*}\,\!} 2348: 2292: 2270: 2248: 2226: 2204: 2182: 2158: 2136: 2114: 2092: 2070: 2048: 2024: 1988: 1966: 1938: 1857: 1788: 1723: 1654: 1615: 1581: 1548: 1521: 1497: 1468: 1439: 1375: 1340: 1314: 1292: 1266: 1239: 1217: 1191: 1159: 1137: 1115: 1085: 1053: 1025: 1003: 970: 948: 926: 874: 818: 796: 774: 752: 730: 699: 677: 655: 633: 611: 576: 548: 520: 498: 476: 453: 431: 371: 331: 303: 280: 256: 231: 205: 169: 132: 89: 10113: 10073: 10042: 9990: 9953: 9871: 9806: 9751: 9723: 9689: 9667: 9639: 9617: 9422: 9394: 9369: 9331: 9306: 9268: 9246: 9224: 9183: 9161: 9139: 9098: 9076: 9036: 9008: 8986: 8958: 8936: 8908: 8875: 8810: 8788: 8766: 8744: 8716: 8680: 8658: 8625: 8603: 8532: 8481: 8448: 8387: 8362: 8336: 8311: 8289: 8264: 8230: 8151: 8129: 8101: 8075: 8053: 8031: 7904: 7882: 7851: 7821: 7799: 7777: 7748: 7721: 7699: 7671: 7557: 7535: 7510: 7386: 7247: 7198: 7155: 7118: 7096: 7074: 6998: 6933: 6868: 6846: 6677: 6613: 6591: 6569: 6547: 6507: 6485: 6463: 6441: 6419: 6397: 6375: 6331: 6309: 6287: 6249: 6227: 6216:. However, the ostensibly simple substitution of 6205: 6036: 6014: 5992: 5958: 5936: 5905: 5877: 5849: 5827: 5805: 5783: 5761: 5739: 5681: 5652: 5624: 5590: 5541: 5465: 5392: 5317: 5295: 5270: 5248: 5226: 5204: 5173: 5151: 5129: 5096: 5029: 5007: 4985: 4949: 4927: 4893: 4871: 4798: 4770: 4734: 4700: 4678: 4656: 4634: 4612: 4536: 4499: 4462: 4431: 4397: 4375: 4335: 4298: 4225: 4160: 4120: 4093: 4056: 4025: 3985: 3948: 3887: 3865: 3826: 3804: 3731: 3700: 3678: 3641: 3619: 3597: 3560: 3538: 3516: 3494: 3457: 3435: 3413: 3385: 3363: 3341: 3306: 3284: 3262: 3240: 3218: 3196: 3174: 3163:T6 asserts that if it is possible to bring about 3146: 3124: 3102: 3080: 3058: 3036: 3012: 2984: 2940: 2856: 2787: 2722: 2653: 2614: 2577: 2517: 2483: 2461: 2439: 2417: 2395: 2373: 2345: 2289: 2267: 2245: 2223: 2201: 2179: 2155: 2133: 2111: 2089: 2067: 2045: 2021: 1985: 1963: 1935: 1854: 1785: 1720: 1651: 1612: 1436: 1372: 1337: 1311: 1289: 1263: 1236: 1214: 1188: 1156: 1134: 1112: 1082: 1050: 1022: 1000: 967: 945: 923: 871: 815: 793: 771: 749: 727: 696: 674: 652: 630: 608: 573: 545: 517: 495: 450: 111:(like "it rains"). The core modal constructs are 10359: 10244:. Englewood Cliffs: Prentice-Hall Inc. pp.  10001:. The approach was later published in 1976 as a 6260:is not so simple as it brings out the so-called 5743:{\displaystyle \langle (x:=x+1)*\rangle x=7\,\!} 5469:{\displaystyle (b=c+x)\leftrightarrow b=c+e\,\!} 5162:containing zero or more instances of a variable 4386:does not. In any such counterexample situation, 2472:must remain true no matter how often we perform 9087:denotes the nondeterministic action of setting 4968:The general form of an assignment statement is 4904:is greater or equal to 3 then after performing 830:to each other, which means they are related by 185:holds. The action language supports operations 10336:Semantical Considerations on Floyd-Hoare Logic 8253:Dynamic logic associates to every proposition 2384:holds now, and no matter how often we perform 10117:{\displaystyle \operatorname {wlp} (a,p)\,\!} 8614:. This action expresses a guarded choice: if 8452:{\displaystyle q\leftrightarrow (p\to q)\,\!} 7166:, then simplify this infinite conjunction to 6320:, we were thinking of the proposition symbol 3840: 3273:is (still) false but one more performance of 2967:is both deterministic and terminating whence 1858:{\displaystyle p\leftrightarrow p\land p\,\!} 1724:{\displaystyle p\leftrightarrow p\land p\,\!} 239:(doing one action or another), and iteration 107:(like "the ground is dry") and a language of 10307:Symposium on Foundations of Computer Science 10131: 10046:{\displaystyle \operatorname {wp} (a,p)\,\!} 9946: 9940: 9365: 9349: 9217: 9201: 8513: 8504: 8477: 8468: 6452:is still the same action after incrementing 5726: 5699: 4852: 4834: 4794: 4788: 3608:is not valid, however, because the truth of 3251:repeatedly to bring about a situation where 3008: 3002: 2930: 2924: 2909: 2900: 2885: 2876: 2849: 2840: 2837: 2831: 2816: 2807: 2780: 2774: 2771: 2765: 2756: 2742: 2715: 2709: 2700: 2694: 2685: 2673: 2640: 2634: 2607: 2601: 2567: 2561: 1426: 1420: 895: 889: 861: 855: 720: 714: 569: 563: 177:, which states that after performing action 161: 155: 140:, which states that after performing action 10179:Temporal logic in finite-state verification 9547: 6430:may impact its truth. Likewise, the action 3527:holds at all times, whence no matter where 2618:{\displaystyle \neg \langle 0\rangle p\,\!} 1948:Axiom A1 makes the empty promise that when 7685:One subtlety we glossed over here is that 5328:. For example, we may instantiate A7 with 5281:, i.e. not bound by some quantifier as in 4711:that are guaranteed to terminate, such as 4616:{\displaystyle (x\geq 3)\to (x\geq 4)\,\!} 10112: 10072: 10041: 9989: 9952: 9870: 9805: 9750: 9722: 9688: 9666: 9638: 9616: 9421: 9393: 9368: 9330: 9305: 9267: 9245: 9223: 9182: 9160: 9138: 9097: 9075: 9035: 9007: 8985: 8957: 8935: 8907: 8874: 8809: 8787: 8765: 8743: 8720:{\displaystyle \neg p?\mathbin {;} b\,\!} 8715: 8679: 8657: 8624: 8602: 8531: 8480: 8447: 8386: 8361: 8335: 8310: 8288: 8263: 8229: 8150: 8128: 8100: 8074: 8052: 8030: 7903: 7881: 7850: 7820: 7798: 7776: 7747: 7720: 7698: 7670: 7556: 7534: 7509: 7385: 7246: 7197: 7154: 7117: 7095: 7073: 6997: 6932: 6867: 6845: 6676: 6612: 6590: 6568: 6546: 6506: 6484: 6462: 6440: 6418: 6396: 6374: 6330: 6308: 6286: 6248: 6226: 6204: 6035: 6013: 5991: 5957: 5935: 5904: 5876: 5848: 5826: 5804: 5782: 5760: 5738: 5680: 5651: 5623: 5589: 5540: 5464: 5391: 5316: 5294: 5269: 5247: 5225: 5203: 5172: 5150: 5128: 5095: 5028: 5006: 4984: 4948: 4926: 4892: 4870: 4797: 4769: 4733: 4699: 4677: 4655: 4633: 4611: 4535: 4498: 4461: 4430: 4396: 4374: 4334: 4297: 4224: 4159: 4119: 4092: 4055: 4024: 3984: 3947: 3886: 3864: 3837:has value 1, and therefore is not valid. 3825: 3803: 3730: 3699: 3677: 3640: 3618: 3596: 3559: 3537: 3515: 3493: 3456: 3434: 3412: 3384: 3362: 3340: 3305: 3283: 3261: 3239: 3229:is true now or it is possible to perform 3217: 3195: 3173: 3145: 3123: 3101: 3079: 3057: 3035: 3011: 2983: 2939: 2855: 2786: 2721: 2652: 2613: 2576: 2516: 2482: 2460: 2438: 2416: 2394: 2372: 2344: 2288: 2266: 2244: 2222: 2200: 2178: 2154: 2132: 2110: 2088: 2066: 2044: 2020: 1984: 1962: 1934: 1853: 1784: 1719: 1650: 1611: 1578: 1518: 1435: 1371: 1336: 1310: 1288: 1262: 1235: 1213: 1187: 1155: 1133: 1111: 1081: 1049: 1021: 999: 966: 944: 922: 870: 814: 792: 770: 748: 726: 695: 673: 651: 629: 607: 572: 544: 516: 494: 449: 10269:Mirkowska, Grażyna; Salwicki A. (1987). 10237: 10213:Nicolas Troquard and Philippe Balbiani, 4302:{\displaystyle (b\to b)\to (b\to b)\,\!} 3845:As for modal logic, the inference rules 1939:{\displaystyle p\land (p\to p)\to p\,\!} 213:(doing one action followed by another), 8402:. Tests can be axiomatized as follows. 7732:is the superscript in the expansion of 7202:{\displaystyle \forall i\Phi (n+i)\,\!} 4229:{\displaystyle b\to b\vdash b\to b\,\!} 3952:{\displaystyle b\to b\vdash b\to b\,\!} 10360: 9080:{\displaystyle x\mathbin {:=} {?}\,\!} 8485:{\displaystyle \langle p?\rangle \,\!} 6558:; if it denotes 3 before incrementing 3876:for the action of kicking the TV, and 2963:changes nothing, bearing in mind that 2406:it remains the case that the truth of 2256:must bring about a situation in which 1789:{\displaystyle p\leftrightarrow p\,\!} 1655:{\displaystyle p\leftrightarrow p\,\!} 731:{\displaystyle \langle a\rangle p\,\!} 8919:zero or more times and then performs 7107:modalities. Then apply Hoare's axiom 5140:can be instantiated with any formula 4802:{\displaystyle \langle a\rangle \,\!} 3016:{\displaystyle \langle 1\rangle \,\!} 577:{\displaystyle \langle a\rangle \,\!} 372:{\displaystyle \varphi \to \varphi '} 8912:{\displaystyle p?\mathbin {;} a\,\!} 8662:{\displaystyle p?\mathbin {;} a\,\!} 6857:, that is, the conjunction over all 6408:as before, even though incrementing 3711:is false, or in any situation where 3689:will be true in any situation where 3571:will be true there. The implication 1192:{\displaystyle a{\mathbin {;}}b\,\!} 1123:, is performed by performing one of 10218:Stanford encyclopedia of philosophy 9051:Quantification as random assignment 7078:{\displaystyle \ldots \Phi (n)\,\!} 5109:This is a schema in the sense that 1383:, does nothing but does terminate. 1203:, is performed by performing first 18:dynamic logic (digital electronics) 13: 10195: 9387: 9324: 9026: 8976: 8926: 8865: 8698: 8582: 8012: 8006: 7973: 7952: 7943: 7928: 7869: 7692: 7658: 7652: 7625: 7610: 7601: 7586: 7491: 7485: 7452: 7431: 7422: 7407: 7367: 7361: 7334: 7292: 7283: 7268: 7179: 7173: 7136: 7061: 6985: 6920: 6827: 6778: 6729: 6664: 6274: 6192: 6141: 6105: 6057: 5923: 5288: 5266: 5222: 5191: 5147: 5116: 5083: 5068: 4236:is sound. However the implication 3808:{\displaystyle (x=1)\to (x=1)\,\!} 2915: 2598: 2570: 2558: 1429: 1417: 963: 941: 916: 904: 864: 852: 170:{\displaystyle \langle a\rangle p} 43:capable of encoding properties of 14: 10389: 10342:Chapter 6 : Logic and Action 10338:(original paper on dynamic logic) 10329: 10262: 9891:nondeterministic exponential time 9565:Propositional dynamic logic (PDL) 7682:, namely mathematical induction. 5635:, which in turn is equivalent to 2506:generalized to arbitrary actions 9930:by expressing the Hoare formula 9235:says that it is possible to set 9055:The random-assignment statement 8549:is realized in dynamic logic as 4960:might be greater or equal to 4. 3815:is false in any situation where 3207:sufficiently often, then either 641:it is necessarily the case that 619:is that after performing action 9922:Dynamic logic was developed by 206:{\displaystyle a\mathbin {;} b} 10352:Lecture Notes on Dynamic Logic 10231: 10215:"Propositional Dynamic Logic." 10137:sequential case. In contrast 10109: 10097: 10066: 10060: 10038: 10026: 9983: 9977: 9974: 9895:deterministic exponential time 9802: 9790: 9787: 9769: 9613: 9601: 9598: 9580: 9526: 9508: 9500: 9486: 9302: 9286: 9132: 9116: 8853: 8835: 8599: 8579: 8573: 8556: 8519: 8461:The corresponding theorem for 8444: 8438: 8432: 8429: 8423: 8414: 8223: 8214: 8211: 8208: 8202: 8196: 8193: 8187: 8184: 8175: 8027: 8015: 8003: 8000: 7997: 7994: 7976: 7970: 7967: 7955: 7949: 7937: 7931: 7925: 7878: 7872: 7667: 7661: 7649: 7646: 7643: 7640: 7628: 7622: 7619: 7613: 7607: 7595: 7589: 7583: 7506: 7494: 7482: 7479: 7476: 7473: 7455: 7449: 7446: 7434: 7428: 7416: 7410: 7404: 7382: 7370: 7358: 7355: 7352: 7349: 7337: 7331: 7313: 7310: 7307: 7295: 7289: 7277: 7271: 7265: 7243: 7237: 7219: 7216: 7194: 7182: 7159:{\displaystyle \Phi (n+i)\,\!} 7151: 7139: 7070: 7064: 7055: 7037: 7034: 7016: 6994: 6988: 6982: 6973: 6954: 6951: 6929: 6923: 6917: 6908: 6889: 6886: 6836: 6830: 6824: 6815: 6796: 6793: 6787: 6781: 6775: 6766: 6747: 6744: 6738: 6732: 6726: 6717: 6698: 6695: 6673: 6667: 6661: 6655: 6637: 6634: 6543: 6525: 6371: 6353: 6283: 6277: 6201: 6195: 6189: 6183: 6165: 6162: 6159: 6156: 6153: 6150: 6144: 6138: 6120: 6117: 6114: 6108: 6102: 6099: 6093: 6075: 6072: 6066: 6060: 6054: 5932: 5926: 5720: 5702: 5577: 5559: 5522: 5519: 5507: 5504: 5486: 5446: 5443: 5425: 5422: 5410: 5372: 5369: 5350: 5347: 5335: 5200: 5194: 5125: 5119: 5092: 5086: 5080: 5077: 5071: 5065: 5053: 4867: 4855: 4831: 4828: 4816: 4766: 4760: 4753:have the same force, that is, 4608: 4596: 4593: 4575: 4572: 4569: 4557: 4529: 4523: 4520: 4492: 4486: 4483: 4455: 4449: 4424: 4415: 4368: 4359: 4356: 4328: 4322: 4319: 4294: 4288: 4279: 4276: 4270: 4267: 4264: 4258: 4252: 4249: 4243: 4218: 4209: 4206: 4194: 4188: 4185: 4153: 4144: 4141: 4086: 4080: 4077: 4049: 4043: 4018: 4009: 4006: 3978: 3972: 3969: 3941: 3932: 3929: 3917: 3911: 3908: 3800: 3788: 3785: 3767: 3764: 3761: 3749: 3724: 3718: 3671: 3665: 3662: 3590: 3584: 3581: 3487: 3481: 3334: 3025:T3 says that if the choice of 2980: 2974: 2936: 2912: 2891: 2822: 2762: 2691: 2646: 2555: 2549: 2543: 2531: 1928: 1919: 1916: 1913: 1907: 1901: 1898: 1892: 1889: 1880: 1847: 1838: 1835: 1829: 1820: 1814: 1805: 1778: 1772: 1769: 1763: 1760: 1754: 1740: 1713: 1707: 1698: 1692: 1689: 1683: 1671: 1644: 1638: 1632: 1605: 1599: 1572: 1566: 1489: 1414: 1408: 1402: 1104: 913: 907: 901: 849: 843: 837: 601: 595: 541: 535: 358: 352: 349: 339:, the dynamic logic statement 124: 118: 76: 68: 65: 1: 10296: 9810:{\displaystyle (x\geq 4)\,\!} 9621:{\displaystyle (x\geq 4)\,\!} 9398:{\displaystyle \exists x\,\!} 9335:{\displaystyle \forall x\,\!} 9172:holds no matter what you set 7703:{\displaystyle \forall i\,\!} 6346:with respect to the modality 5628:{\displaystyle x+1\geq 4\,\!} 5299:{\displaystyle \forall x\,\!} 4963: 3498:{\displaystyle p\vdash p\,\!} 3417:{\displaystyle p\vdash q\,\!} 2034:A3 says that if doing one of 1498:{\displaystyle \vdash p\to q} 1278:, is performed by performing 461:is necessarily the case, and 10224: 10084:corresponding to Dijkstra's 8727:is equivalent to BLOCK, and 7886:{\displaystyle \Phi (n)\,\!} 7002:{\displaystyle \Phi (n)\,\!} 6937:{\displaystyle \Phi (n)\,\!} 6688:as the infinite conjunction 6681:{\displaystyle \Phi (n)\,\!} 6291:{\displaystyle \Phi (n)\,\!} 5940:{\displaystyle \Phi (n)\,\!} 5772:sufficiently often, to make 5208:{\displaystyle \Phi (e)\,\!} 5133:{\displaystyle \Phi (x)\,\!} 1447:and the two inference rules 971:{\displaystyle \exists \,\!} 949:{\displaystyle \forall \,\!} 33:theoretical computer science 7: 10241:A Discipline of Programming 10156: 9957:{\displaystyle p\{a\}q\,\!} 9755:{\displaystyle x\geq 4\,\!} 9040:{\displaystyle \neg p?\,\!} 8990:{\displaystyle \neg p?\,\!} 8940:{\displaystyle \neg p?\,\!} 8748:{\displaystyle a\cup 0\,\!} 6474:, even though incrementing 5881:{\displaystyle x\leq 7\,\!} 5656:{\displaystyle x\geq 3\,\!} 5594:{\displaystyle x\geq 4\,\!} 3742:is true, but the assertion 1054:{\displaystyle a\cup b\,\!} 484:(diamond p) asserting that 405: 10: 10394: 9994:{\displaystyle p\to q\,\!} 9917: 9910:(1978), Pratt (1979), and 9875:{\displaystyle x:=x+1\,\!} 9727:{\displaystyle x:=x+1\,\!} 9628:contains all three types: 5996:{\displaystyle n:=n+1\,\!} 5237:with those occurrences of 4931:{\displaystyle x:=x+1\,\!} 4738:{\displaystyle x:=x+1\,\!} 4540:{\displaystyle b\to b\,\!} 4503:{\displaystyle b\to b\,\!} 4379:{\displaystyle b\to b\,\!} 4339:{\displaystyle b\to b\,\!} 4164:{\displaystyle b\to b\,\!} 4097:{\displaystyle b\to b\,\!} 4029:{\displaystyle b\to b\,\!} 3989:{\displaystyle b\to b\,\!} 3841:Derived rules of inference 3682:{\displaystyle p\to p\,\!} 3601:{\displaystyle p\to p\,\!} 3345:{\displaystyle p\to q\,\!} 3161:T5 is explained as for A5. 1582:{\displaystyle \vdash p\,} 1522:{\displaystyle \vdash q\,} 477:{\displaystyle \Diamond p} 15: 10373:Logic in computer science 10184:Temporal logic of actions 10132:The concurrency challenge 9561:including dynamic logic. 7788:over all natural numbers 7781:{\displaystyle a^{i}\,\!} 7129:times to this to produce 5274:{\displaystyle \Phi \,\!} 5230:{\displaystyle \Phi \,\!} 5155:{\displaystyle \Phi \,\!} 1386: 738:is that after performing 332:{\displaystyle \varphi '} 9887:computational complexity 9548:Possible-world semantics 9426:{\displaystyle x:=?\,\!} 7752:{\displaystyle a{*}\,\!} 4989:{\displaystyle x:=e\,\!} 4124:{\displaystyle k{*}\,\!} 3135:alone could bring about 2494:. A6 is recognizable as 1549:{\displaystyle \vdash p} 1469:{\displaystyle \vdash p} 1376:{\displaystyle 0{*}\,\!} 1267:{\displaystyle a{*}\,\!} 413:is characterized by the 304:{\displaystyle \varphi } 10238:Dijkstra, E.W. (1976). 9823:propositional variables 9671:{\displaystyle x+1\,\!} 9109:to an arbitrary value. 8248: 8133:{\displaystyle n+i\,\!} 8064:in that state, as when 7862:is a real variable and 7568:in the usual manner of 6944:. Now apply A4 to turn 1167:. The compound action 1116:{\displaystyle a|b\,\!} 1086:{\displaystyle a+b\,\!} 439:(box p) asserting that 232:{\displaystyle a\cup b} 10126:predicate transformers 10118: 10078: 10047: 9995: 9958: 9876: 9811: 9756: 9728: 9694: 9672: 9644: 9622: 9538: 9473: 9453: 9427: 9399: 9374: 9336: 9311: 9273: 9257:to a value that makes 9251: 9229: 9188: 9166: 9144: 9103: 9081: 9041: 9013: 8991: 8963: 8941: 8913: 8880: 8815: 8793: 8771: 8749: 8721: 8685: 8663: 8630: 8608: 8537: 8486: 8453: 8392: 8391:{\displaystyle p?\,\!} 8367: 8341: 8340:{\displaystyle p?\,\!} 8316: 8294: 8293:{\displaystyle p?\,\!} 8269: 8235: 8156: 8134: 8106: 8090:. If in a given state 8080: 8058: 8036: 7909: 7887: 7856: 7826: 7804: 7782: 7753: 7726: 7704: 7676: 7562: 7540: 7515: 7391: 7252: 7203: 7160: 7123: 7101: 7079: 7003: 6938: 6873: 6851: 6682: 6618: 6596: 6574: 6552: 6512: 6490: 6468: 6446: 6424: 6402: 6380: 6336: 6314: 6292: 6254: 6232: 6210: 6041: 6019: 5997: 5963: 5941: 5910: 5892:Mathematical induction 5882: 5854: 5832: 5810: 5788: 5766: 5744: 5686: 5657: 5629: 5595: 5546: 5470: 5397: 5322: 5300: 5275: 5253: 5231: 5209: 5178: 5156: 5134: 5101: 5034: 5012: 4990: 4954: 4932: 4898: 4876: 4803: 4775: 4739: 4705: 4683: 4661: 4639: 4617: 4541: 4504: 4467: 4436: 4402: 4380: 4340: 4303: 4230: 4165: 4125: 4098: 4061: 4030: 3990: 3953: 3892: 3870: 3831: 3809: 3736: 3705: 3683: 3646: 3624: 3602: 3565: 3543: 3521: 3499: 3462: 3440: 3418: 3390: 3368: 3346: 3311: 3289: 3267: 3245: 3223: 3201: 3179: 3151: 3129: 3107: 3085: 3063: 3041: 3017: 2989: 2945: 2861: 2792: 2727: 2658: 2619: 2582: 2536:The modal logic axiom 2522: 2496:mathematical induction 2488: 2466: 2444: 2422: 2400: 2378: 2350: 2294: 2272: 2250: 2228: 2206: 2184: 2168:A4 says that if doing 2160: 2138: 2116: 2094: 2072: 2050: 2026: 1990: 1968: 1940: 1859: 1790: 1725: 1656: 1617: 1583: 1550: 1523: 1499: 1470: 1441: 1377: 1342: 1316: 1294: 1268: 1247:. The compound action 1241: 1219: 1193: 1161: 1139: 1117: 1087: 1055: 1033:, the compound action 1027: 1005: 972: 950: 928: 876: 820: 798: 776: 754: 732: 701: 679: 657: 635: 613: 584:, thereby making it a 578: 550: 522: 500: 478: 455: 433: 432:{\displaystyle \Box p} 373: 333: 305: 282: 258: 233: 207: 171: 134: 91: 10119: 10079: 10077:{\displaystyle p\,\!} 10048: 9996: 9959: 9877: 9812: 9757: 9729: 9695: 9693:{\displaystyle 4\,\!} 9673: 9645: 9643:{\displaystyle x\,\!} 9623: 9539: 9474: 9454: 9428: 9400: 9375: 9337: 9312: 9274: 9272:{\displaystyle p\,\!} 9252: 9250:{\displaystyle x\,\!} 9230: 9189: 9187:{\displaystyle x\,\!} 9167: 9165:{\displaystyle p\,\!} 9145: 9143:{\displaystyle p\,\!} 9104: 9102:{\displaystyle x\,\!} 9082: 9042: 9014: 9012:{\displaystyle p\,\!} 8992: 8964: 8962:{\displaystyle p\,\!} 8942: 8914: 8881: 8816: 8814:{\displaystyle p\,\!} 8794: 8792:{\displaystyle p\,\!} 8772: 8770:{\displaystyle a\,\!} 8750: 8722: 8686: 8684:{\displaystyle a\,\!} 8664: 8631: 8629:{\displaystyle p\,\!} 8609: 8538: 8487: 8454: 8393: 8368: 8366:{\displaystyle p\,\!} 8342: 8317: 8315:{\displaystyle p\,\!} 8295: 8270: 8268:{\displaystyle p\,\!} 8236: 8157: 8155:{\displaystyle n\,\!} 8135: 8107: 8105:{\displaystyle n\,\!} 8081: 8079:{\displaystyle n\,\!} 8059: 8057:{\displaystyle n\,\!} 8037: 7910: 7908:{\displaystyle n\,\!} 7888: 7857: 7855:{\displaystyle n\,\!} 7827: 7825:{\displaystyle n\,\!} 7805: 7803:{\displaystyle i\,\!} 7783: 7754: 7727: 7725:{\displaystyle i\,\!} 7705: 7677: 7563: 7561:{\displaystyle n\,\!} 7541: 7539:{\displaystyle 0\,\!} 7516: 7392: 7253: 7204: 7161: 7124: 7122:{\displaystyle i\,\!} 7102: 7100:{\displaystyle i\,\!} 7080: 7004: 6939: 6874: 6872:{\displaystyle i\,\!} 6852: 6683: 6619: 6617:{\displaystyle n\,\!} 6597: 6595:{\displaystyle 0\,\!} 6575: 6573:{\displaystyle n\,\!} 6553: 6513: 6511:{\displaystyle n\,\!} 6491: 6489:{\displaystyle n\,\!} 6469: 6467:{\displaystyle n\,\!} 6447: 6445:{\displaystyle a\,\!} 6425: 6423:{\displaystyle n\,\!} 6403: 6401:{\displaystyle n\,\!} 6381: 6337: 6335:{\displaystyle p\,\!} 6315: 6313:{\displaystyle p\,\!} 6293: 6255: 6253:{\displaystyle n\,\!} 6233: 6231:{\displaystyle 0\,\!} 6211: 6042: 6040:{\displaystyle 0\,\!} 6020: 6018:{\displaystyle n\,\!} 5998: 5964: 5962:{\displaystyle a\,\!} 5942: 5911: 5909:{\displaystyle p\,\!} 5883: 5855: 5853:{\displaystyle x\,\!} 5833: 5831:{\displaystyle x\,\!} 5811: 5809:{\displaystyle x\,\!} 5789: 5787:{\displaystyle x\,\!} 5767: 5765:{\displaystyle x\,\!} 5745: 5687: 5685:{\displaystyle *\,\!} 5658: 5630: 5596: 5547: 5471: 5398: 5323: 5321:{\displaystyle e\,\!} 5301: 5276: 5254: 5252:{\displaystyle x\,\!} 5232: 5210: 5179: 5177:{\displaystyle x\,\!} 5157: 5135: 5102: 5035: 5033:{\displaystyle e\,\!} 5013: 5011:{\displaystyle x\,\!} 4991: 4955: 4953:{\displaystyle x\,\!} 4933: 4899: 4897:{\displaystyle x\,\!} 4877: 4804: 4776: 4740: 4706: 4704:{\displaystyle a\,\!} 4684: 4682:{\displaystyle x\,\!} 4662: 4660:{\displaystyle x\,\!} 4640: 4638:{\displaystyle x\,\!} 4618: 4542: 4505: 4468: 4466:{\displaystyle b\,\!} 4442:must be false, while 4437: 4435:{\displaystyle b\,\!} 4403: 4401:{\displaystyle b\,\!} 4381: 4341: 4304: 4231: 4166: 4126: 4099: 4062: 4060:{\displaystyle b\,\!} 4031: 3991: 3954: 3893: 3891:{\displaystyle b\,\!} 3871: 3869:{\displaystyle k\,\!} 3832: 3830:{\displaystyle x\,\!} 3810: 3737: 3735:{\displaystyle p\,\!} 3706: 3704:{\displaystyle p\,\!} 3684: 3647: 3645:{\displaystyle a\,\!} 3625: 3623:{\displaystyle p\,\!} 3603: 3566: 3564:{\displaystyle p\,\!} 3544: 3542:{\displaystyle a\,\!} 3522: 3520:{\displaystyle p\,\!} 3500: 3463: 3461:{\displaystyle q\,\!} 3441: 3439:{\displaystyle p\,\!} 3419: 3391: 3389:{\displaystyle q\,\!} 3369: 3367:{\displaystyle p\,\!} 3347: 3312: 3310:{\displaystyle p\,\!} 3290: 3288:{\displaystyle a\,\!} 3268: 3266:{\displaystyle p\,\!} 3246: 3244:{\displaystyle a\,\!} 3224: 3222:{\displaystyle p\,\!} 3202: 3200:{\displaystyle a\,\!} 3180: 3178:{\displaystyle p\,\!} 3152: 3150:{\displaystyle p\,\!} 3130: 3128:{\displaystyle b\,\!} 3108: 3106:{\displaystyle a\,\!} 3086: 3084:{\displaystyle p\,\!} 3064: 3062:{\displaystyle b\,\!} 3042: 3040:{\displaystyle a\,\!} 3018: 2990: 2946: 2862: 2793: 2728: 2659: 2620: 2583: 2523: 2521:{\displaystyle a\,\!} 2489: 2487:{\displaystyle a\,\!} 2467: 2465:{\displaystyle p\,\!} 2445: 2443:{\displaystyle a\,\!} 2423: 2421:{\displaystyle p\,\!} 2401: 2399:{\displaystyle a\,\!} 2379: 2377:{\displaystyle p\,\!} 2351: 2295: 2293:{\displaystyle p\,\!} 2273: 2271:{\displaystyle b\,\!} 2251: 2249:{\displaystyle a\,\!} 2229: 2227:{\displaystyle p\,\!} 2207: 2205:{\displaystyle b\,\!} 2185: 2183:{\displaystyle a\,\!} 2161: 2159:{\displaystyle b\,\!} 2139: 2137:{\displaystyle p\,\!} 2117: 2115:{\displaystyle a\,\!} 2095: 2093:{\displaystyle p\,\!} 2073: 2071:{\displaystyle b\,\!} 2051: 2049:{\displaystyle a\,\!} 2027: 2025:{\displaystyle p\,\!} 1991: 1989:{\displaystyle p\,\!} 1969: 1967:{\displaystyle p\,\!} 1941: 1860: 1791: 1726: 1657: 1618: 1616:{\displaystyle p\,\!} 1584: 1551: 1524: 1500: 1471: 1442: 1378: 1343: 1341:{\displaystyle 1\,\!} 1317: 1315:{\displaystyle 0\,\!} 1295: 1293:{\displaystyle a\,\!} 1269: 1242: 1240:{\displaystyle b\,\!} 1220: 1218:{\displaystyle a\,\!} 1194: 1162: 1160:{\displaystyle b\,\!} 1140: 1138:{\displaystyle a\,\!} 1118: 1088: 1056: 1028: 1026:{\displaystyle b\,\!} 1006: 1004:{\displaystyle a\,\!} 973: 951: 929: 877: 821: 819:{\displaystyle p\,\!} 799: 797:{\displaystyle a\,\!} 777: 775:{\displaystyle p\,\!} 755: 753:{\displaystyle a\,\!} 733: 702: 700:{\displaystyle p\,\!} 680: 678:{\displaystyle a\,\!} 658: 656:{\displaystyle p\,\!} 636: 634:{\displaystyle a\,\!} 614: 612:{\displaystyle p\,\!} 579: 551: 523: 521:{\displaystyle a\,\!} 501: 499:{\displaystyle p\,\!} 479: 456: 454:{\displaystyle p\,\!} 434: 374: 334: 306: 283: 259: 234: 208: 172: 135: 92: 10088: 10057: 10017: 9968: 9934: 9906:(unpublished note), 9852: 9766: 9738: 9704: 9682: 9654: 9632: 9577: 9483: 9463: 9443: 9409: 9384: 9346: 9321: 9310:{\displaystyle \,\!} 9283: 9261: 9239: 9198: 9176: 9154: 9113: 9091: 9059: 9023: 9001: 8973: 8951: 8923: 8890: 8832: 8821:is false the right. 8803: 8781: 8759: 8731: 8695: 8673: 8640: 8618: 8553: 8501: 8465: 8411: 8377: 8355: 8326: 8304: 8300:called a test. When 8279: 8257: 8166: 8144: 8116: 8094: 8068: 8046: 7922: 7897: 7866: 7844: 7814: 7792: 7763: 7736: 7714: 7689: 7580: 7576:'s celebrated axiom 7550: 7528: 7401: 7262: 7251:{\displaystyle \,\!} 7213: 7170: 7133: 7111: 7089: 7013: 6948: 6883: 6861: 6692: 6631: 6606: 6584: 6562: 6551:{\displaystyle \,\!} 6522: 6500: 6478: 6456: 6434: 6412: 6390: 6379:{\displaystyle \,\!} 6350: 6324: 6302: 6271: 6267:When we substituted 6242: 6220: 6051: 6029: 6007: 5973: 5951: 5920: 5898: 5864: 5842: 5820: 5798: 5776: 5754: 5696: 5674: 5639: 5605: 5556: 5483: 5407: 5332: 5310: 5285: 5263: 5241: 5219: 5188: 5166: 5144: 5113: 5050: 5022: 5000: 4972: 4942: 4908: 4886: 4813: 4785: 4774:{\displaystyle \,\!} 4757: 4715: 4693: 4671: 4649: 4627: 4623:. This says that if 4554: 4514: 4477: 4446: 4412: 4390: 4350: 4313: 4240: 4179: 4135: 4108: 4071: 4040: 4000: 3963: 3959:, having as premise 3902: 3880: 3858: 3819: 3746: 3715: 3693: 3656: 3634: 3612: 3575: 3553: 3531: 3509: 3472: 3450: 3446:is valid then so is 3428: 3400: 3378: 3356: 3328: 3299: 3277: 3255: 3233: 3211: 3189: 3167: 3139: 3117: 3095: 3073: 3051: 3029: 3023:have the same force. 2999: 2988:{\displaystyle \,\!} 2971: 2959:T2 notes again that 2873: 2804: 2739: 2670: 2631: 2595: 2540: 2510: 2476: 2454: 2432: 2410: 2388: 2366: 2306: 2282: 2260: 2238: 2216: 2194: 2172: 2148: 2126: 2104: 2082: 2060: 2038: 2014: 1978: 1956: 1871: 1802: 1737: 1668: 1629: 1596: 1560: 1537: 1509: 1480: 1457: 1399: 1360: 1330: 1304: 1282: 1251: 1229: 1207: 1171: 1149: 1127: 1097: 1069: 1037: 1015: 993: 960: 938: 886: 834: 808: 786: 764: 760:it is possible that 742: 711: 689: 667: 645: 623: 592: 560: 549:{\displaystyle \,\!} 532: 528:the modal operators 510: 488: 465: 443: 420: 402:, and other fields. 343: 318: 295: 272: 257:{\displaystyle a{*}} 243: 217: 189: 181:it is possible that 152: 115: 57: 10378:Non-classical logic 9914:and Parikh (1981). 9819:Propositional logic 7916:is a natural number 6262:referential opacity 5916:is instantiated as 5692:is the proposition 5259:that occur free in 3374:is true then so is 3159:T4 is just like A4. 2362:A6 asserts that if 1996:is the proposition 1974:will hold, even if 956:) and existential ( 826:. These operators 388:formal verification 39:is an extension of 10141:'s 1977 system of 10114: 10074: 10043: 9991: 9954: 9872: 9842:Michael J. Fischer 9807: 9752: 9734:is an action, and 9724: 9690: 9668: 9640: 9618: 9534: 9469: 9449: 9423: 9395: 9370: 9332: 9307: 9269: 9247: 9225: 9184: 9162: 9140: 9099: 9077: 9037: 9009: 8987: 8969:remains true, the 8959: 8937: 8909: 8876: 8811: 8789: 8767: 8745: 8717: 8681: 8659: 8626: 8604: 8547:if p then a else b 8533: 8482: 8449: 8388: 8363: 8337: 8312: 8290: 8265: 8231: 8152: 8130: 8102: 8076: 8054: 8032: 7905: 7883: 7852: 7822: 7800: 7778: 7749: 7722: 7700: 7672: 7558: 7536: 7511: 7387: 7248: 7199: 7156: 7119: 7097: 7075: 6999: 6934: 6869: 6847: 6678: 6624:everywhere in A6. 6614: 6592: 6570: 6548: 6508: 6486: 6464: 6442: 6420: 6398: 6376: 6332: 6310: 6288: 6250: 6228: 6206: 6037: 6015: 5993: 5959: 5937: 5906: 5878: 5850: 5828: 5806: 5784: 5762: 5740: 5682: 5665:elementary algebra 5653: 5625: 5591: 5542: 5466: 5393: 5318: 5296: 5271: 5249: 5227: 5205: 5174: 5152: 5130: 5097: 5030: 5018:is a variable and 5008: 4986: 4950: 4928: 4894: 4882:asserting that if 4872: 4799: 4771: 4735: 4701: 4679: 4657: 4635: 4613: 4537: 4500: 4463: 4432: 4398: 4376: 4336: 4299: 4226: 4161: 4121: 4094: 4057: 4026: 3996:and as conclusion 3986: 3949: 3888: 3866: 3827: 3805: 3732: 3701: 3679: 3642: 3620: 3598: 3561: 3539: 3517: 3495: 3458: 3436: 3414: 3386: 3364: 3342: 3307: 3295:could bring about 3285: 3263: 3241: 3219: 3197: 3175: 3147: 3125: 3103: 3081: 3069:could bring about 3059: 3037: 3013: 2985: 2941: 2857: 2788: 2723: 2654: 2615: 2578: 2518: 2484: 2462: 2440: 2418: 2396: 2374: 2346: 2290: 2268: 2246: 2224: 2202: 2180: 2156: 2134: 2112: 2090: 2068: 2046: 2022: 1986: 1964: 1936: 1855: 1786: 1721: 1652: 1613: 1579: 1546: 1519: 1495: 1466: 1437: 1373: 1338: 1312: 1290: 1264: 1237: 1215: 1189: 1157: 1135: 1113: 1083: 1051: 1023: 1001: 987:regular expression 968: 946: 924: 872: 816: 804:might bring about 794: 772: 750: 728: 707:. The meaning of 697: 675: 653: 631: 609: 588:. The meaning of 574: 546: 518: 496: 474: 451: 429: 386:Beyond its use in 369: 329: 301: 278: 266:Boolean operations 254: 229: 203: 167: 130: 87: 10272:Algorithmic Logic 10153:, fairness, etc. 10007:algorithmic logic 9571:first-order logic 9472:{\displaystyle x} 9452:{\displaystyle x} 8755:is equivalent to 8669:is equivalent to 7893:is the predicate 7832:had been of type 7570:first-order logic 5184:. The meaning of 4036:. The meaning of 2278:must bring about 2212:must bring about 2166:, and conversely. 2144:and likewise for 2122:must bring about 2078:must bring about 685:must bring about 281:{\displaystyle P} 148:should hold, and 133:{\displaystyle p} 82: 81:The ground is wet 74: 63: 62:The ground is dry 45:computer programs 10385: 10354:by André Platzer 10309:, 1976, 109-121. 10290: 10289: 10277: 10266: 10260: 10259: 10235: 10189:Modal μ-calculus 10123: 10121: 10120: 10115: 10083: 10081: 10080: 10075: 10052: 10050: 10049: 10044: 10000: 9998: 9997: 9992: 9963: 9961: 9960: 9955: 9881: 9879: 9878: 9873: 9817:are assertions. 9816: 9814: 9813: 9808: 9761: 9759: 9758: 9753: 9733: 9731: 9730: 9725: 9699: 9697: 9696: 9691: 9677: 9675: 9674: 9669: 9649: 9647: 9646: 9641: 9627: 9625: 9624: 9619: 9559:systems of logic 9543: 9541: 9540: 9535: 9533: 9507: 9496: 9478: 9476: 9475: 9470: 9458: 9456: 9455: 9450: 9432: 9430: 9429: 9424: 9404: 9402: 9401: 9396: 9379: 9377: 9376: 9371: 9364: 9359: 9341: 9339: 9338: 9333: 9316: 9314: 9313: 9308: 9301: 9296: 9278: 9276: 9275: 9270: 9256: 9254: 9253: 9248: 9234: 9232: 9231: 9226: 9216: 9211: 9193: 9191: 9190: 9185: 9171: 9169: 9168: 9163: 9149: 9147: 9146: 9141: 9131: 9126: 9108: 9106: 9105: 9100: 9086: 9084: 9083: 9078: 9074: 9069: 9046: 9044: 9043: 9038: 9018: 9016: 9015: 9010: 8996: 8994: 8993: 8988: 8968: 8966: 8965: 8960: 8946: 8944: 8943: 8938: 8918: 8916: 8915: 8910: 8903: 8886:. This performs 8885: 8883: 8882: 8877: 8864: 8859: 8849: 8820: 8818: 8817: 8812: 8798: 8796: 8795: 8790: 8776: 8774: 8773: 8768: 8754: 8752: 8751: 8746: 8726: 8724: 8723: 8718: 8711: 8690: 8688: 8687: 8682: 8668: 8666: 8665: 8660: 8653: 8635: 8633: 8632: 8627: 8613: 8611: 8610: 8605: 8595: 8569: 8542: 8540: 8539: 8534: 8491: 8489: 8488: 8483: 8458: 8456: 8455: 8450: 8397: 8395: 8394: 8389: 8372: 8370: 8369: 8364: 8346: 8344: 8343: 8338: 8322:holds, the test 8321: 8319: 8318: 8313: 8299: 8297: 8296: 8291: 8274: 8272: 8271: 8266: 8240: 8238: 8237: 8232: 8161: 8159: 8158: 8153: 8139: 8137: 8136: 8131: 8111: 8109: 8108: 8103: 8085: 8083: 8082: 8077: 8063: 8061: 8060: 8055: 8041: 8039: 8038: 8033: 7914: 7912: 7911: 7906: 7892: 7890: 7889: 7884: 7861: 7859: 7858: 7853: 7831: 7829: 7828: 7823: 7809: 7807: 7806: 7801: 7787: 7785: 7784: 7779: 7775: 7774: 7759:as the union of 7758: 7756: 7755: 7750: 7746: 7731: 7729: 7728: 7723: 7709: 7707: 7706: 7701: 7681: 7679: 7678: 7673: 7567: 7565: 7564: 7559: 7545: 7543: 7542: 7537: 7520: 7518: 7517: 7512: 7396: 7394: 7393: 7388: 7258:in A6, yielding 7257: 7255: 7254: 7249: 7208: 7206: 7205: 7200: 7165: 7163: 7162: 7157: 7128: 7126: 7125: 7120: 7106: 7104: 7103: 7098: 7084: 7082: 7081: 7076: 7008: 7006: 7005: 7000: 6981: 6980: 6943: 6941: 6940: 6935: 6916: 6915: 6878: 6876: 6875: 6870: 6856: 6854: 6853: 6848: 6823: 6822: 6774: 6773: 6725: 6724: 6687: 6685: 6684: 6679: 6623: 6621: 6620: 6615: 6601: 6599: 6598: 6593: 6579: 6577: 6576: 6571: 6557: 6555: 6554: 6549: 6517: 6515: 6514: 6509: 6495: 6493: 6492: 6487: 6473: 6471: 6470: 6465: 6451: 6449: 6448: 6443: 6429: 6427: 6426: 6421: 6407: 6405: 6404: 6399: 6385: 6383: 6382: 6377: 6344:rigid designator 6341: 6339: 6338: 6333: 6319: 6317: 6316: 6311: 6297: 6295: 6294: 6289: 6259: 6257: 6256: 6251: 6237: 6235: 6234: 6229: 6215: 6213: 6212: 6207: 6046: 6044: 6043: 6038: 6024: 6022: 6021: 6016: 6002: 6000: 5999: 5994: 5968: 5966: 5965: 5960: 5946: 5944: 5943: 5938: 5915: 5913: 5912: 5907: 5887: 5885: 5884: 5879: 5859: 5857: 5856: 5851: 5837: 5835: 5834: 5829: 5815: 5813: 5812: 5807: 5793: 5791: 5790: 5785: 5771: 5769: 5768: 5763: 5749: 5747: 5746: 5741: 5691: 5689: 5688: 5683: 5662: 5660: 5659: 5654: 5634: 5632: 5631: 5626: 5600: 5598: 5597: 5592: 5551: 5549: 5548: 5543: 5475: 5473: 5472: 5467: 5402: 5400: 5399: 5394: 5390: 5389: 5368: 5367: 5327: 5325: 5324: 5319: 5305: 5303: 5302: 5297: 5280: 5278: 5277: 5272: 5258: 5256: 5255: 5250: 5236: 5234: 5233: 5228: 5214: 5212: 5211: 5206: 5183: 5181: 5180: 5175: 5161: 5159: 5158: 5153: 5139: 5137: 5136: 5131: 5106: 5104: 5103: 5098: 5039: 5037: 5036: 5031: 5017: 5015: 5014: 5009: 4995: 4993: 4992: 4987: 4959: 4957: 4956: 4951: 4937: 4935: 4934: 4929: 4903: 4901: 4900: 4895: 4881: 4879: 4878: 4873: 4808: 4806: 4805: 4800: 4780: 4778: 4777: 4772: 4744: 4742: 4741: 4736: 4710: 4708: 4707: 4702: 4688: 4686: 4685: 4680: 4666: 4664: 4663: 4658: 4644: 4642: 4641: 4636: 4622: 4620: 4619: 4614: 4546: 4544: 4543: 4538: 4509: 4507: 4506: 4501: 4472: 4470: 4469: 4464: 4441: 4439: 4438: 4433: 4407: 4405: 4404: 4399: 4385: 4383: 4382: 4377: 4345: 4343: 4342: 4337: 4308: 4306: 4305: 4300: 4235: 4233: 4232: 4227: 4170: 4168: 4167: 4162: 4130: 4128: 4127: 4122: 4118: 4103: 4101: 4100: 4095: 4066: 4064: 4063: 4058: 4035: 4033: 4032: 4027: 3995: 3993: 3992: 3987: 3958: 3956: 3955: 3950: 3897: 3895: 3894: 3889: 3875: 3873: 3872: 3867: 3836: 3834: 3833: 3828: 3814: 3812: 3811: 3806: 3741: 3739: 3738: 3733: 3710: 3708: 3707: 3702: 3688: 3686: 3685: 3680: 3651: 3649: 3648: 3643: 3629: 3627: 3626: 3621: 3607: 3605: 3604: 3599: 3570: 3568: 3567: 3562: 3548: 3546: 3545: 3540: 3526: 3524: 3523: 3518: 3504: 3502: 3501: 3496: 3467: 3465: 3464: 3459: 3445: 3443: 3442: 3437: 3424:asserts that if 3423: 3421: 3420: 3415: 3396:, the inference 3395: 3393: 3392: 3387: 3373: 3371: 3370: 3365: 3352:asserts that if 3351: 3349: 3348: 3343: 3316: 3314: 3313: 3308: 3294: 3292: 3291: 3286: 3272: 3270: 3269: 3264: 3250: 3248: 3247: 3242: 3228: 3226: 3225: 3220: 3206: 3204: 3203: 3198: 3184: 3182: 3181: 3176: 3156: 3154: 3153: 3148: 3134: 3132: 3131: 3126: 3112: 3110: 3109: 3104: 3090: 3088: 3087: 3082: 3068: 3066: 3065: 3060: 3046: 3044: 3043: 3038: 3022: 3020: 3019: 3014: 2994: 2992: 2991: 2986: 2950: 2948: 2947: 2942: 2866: 2864: 2863: 2858: 2797: 2795: 2794: 2789: 2752: 2732: 2730: 2729: 2724: 2663: 2661: 2660: 2655: 2624: 2622: 2621: 2616: 2587: 2585: 2584: 2579: 2527: 2525: 2524: 2519: 2502:of incrementing 2498:with the action 2493: 2491: 2490: 2485: 2471: 2469: 2468: 2463: 2449: 2447: 2446: 2441: 2427: 2425: 2424: 2419: 2405: 2403: 2402: 2397: 2383: 2381: 2380: 2375: 2355: 2353: 2352: 2347: 2343: 2335: 2334: 2316: 2299: 2297: 2296: 2291: 2277: 2275: 2274: 2269: 2255: 2253: 2252: 2247: 2233: 2231: 2230: 2225: 2211: 2209: 2208: 2203: 2189: 2187: 2186: 2181: 2165: 2163: 2162: 2157: 2143: 2141: 2140: 2135: 2121: 2119: 2118: 2113: 2099: 2097: 2096: 2091: 2077: 2075: 2074: 2069: 2055: 2053: 2052: 2047: 2031: 2029: 2028: 2023: 1995: 1993: 1992: 1987: 1973: 1971: 1970: 1965: 1945: 1943: 1942: 1937: 1864: 1862: 1861: 1856: 1795: 1793: 1792: 1787: 1750: 1730: 1728: 1727: 1722: 1661: 1659: 1658: 1653: 1622: 1620: 1619: 1614: 1588: 1586: 1585: 1580: 1555: 1553: 1552: 1547: 1528: 1526: 1525: 1520: 1504: 1502: 1501: 1496: 1475: 1473: 1472: 1467: 1446: 1444: 1443: 1438: 1382: 1380: 1379: 1374: 1370: 1347: 1345: 1344: 1339: 1321: 1319: 1318: 1313: 1299: 1297: 1296: 1291: 1273: 1271: 1270: 1265: 1261: 1246: 1244: 1243: 1238: 1224: 1222: 1221: 1216: 1198: 1196: 1195: 1190: 1183: 1182: 1166: 1164: 1163: 1158: 1144: 1142: 1141: 1136: 1122: 1120: 1119: 1114: 1107: 1092: 1090: 1089: 1084: 1060: 1058: 1057: 1052: 1032: 1030: 1029: 1024: 1010: 1008: 1007: 1002: 977: 975: 974: 969: 955: 953: 952: 947: 933: 931: 930: 925: 881: 879: 878: 873: 825: 823: 822: 817: 803: 801: 800: 795: 782:holds, that is, 781: 779: 778: 773: 759: 757: 756: 751: 737: 735: 734: 729: 706: 704: 703: 698: 684: 682: 681: 676: 663:holds, that is, 662: 660: 659: 654: 640: 638: 637: 632: 618: 616: 615: 610: 586:multimodal logic 583: 581: 580: 575: 555: 553: 552: 547: 527: 525: 524: 519: 505: 503: 502: 497: 483: 481: 480: 475: 460: 458: 457: 452: 438: 436: 435: 430: 378: 376: 375: 370: 368: 338: 336: 335: 330: 328: 310: 308: 307: 302: 287: 285: 284: 279: 263: 261: 260: 255: 253: 238: 236: 235: 230: 212: 210: 209: 204: 199: 176: 174: 173: 168: 144:the proposition 139: 137: 136: 131: 96: 94: 93: 88: 83: 80: 75: 72: 64: 61: 10393: 10392: 10388: 10387: 10386: 10384: 10383: 10382: 10358: 10357: 10346:Logic In Action 10332: 10299: 10294: 10293: 10286: 10275: 10267: 10263: 10256: 10236: 10232: 10227: 10198: 10196:Further reading 10193: 10159: 10134: 10089: 10086: 10085: 10058: 10055: 10054: 10018: 10015: 10014: 10011:Edsger Dijkstra 9969: 9966: 9965: 9935: 9932: 9931: 9920: 9893:, and at least 9853: 9850: 9849: 9767: 9764: 9763: 9739: 9736: 9735: 9705: 9702: 9701: 9683: 9680: 9679: 9655: 9652: 9651: 9633: 9630: 9629: 9578: 9575: 9574: 9567: 9550: 9529: 9503: 9492: 9484: 9481: 9480: 9464: 9461: 9460: 9444: 9441: 9440: 9410: 9407: 9406: 9385: 9382: 9381: 9360: 9355: 9347: 9344: 9343: 9322: 9319: 9318: 9297: 9292: 9284: 9281: 9280: 9262: 9259: 9258: 9240: 9237: 9236: 9212: 9207: 9199: 9196: 9195: 9177: 9174: 9173: 9155: 9152: 9151: 9150:then says that 9127: 9122: 9114: 9111: 9110: 9092: 9089: 9088: 9070: 9065: 9060: 9057: 9056: 9053: 9024: 9021: 9020: 9002: 8999: 8998: 8974: 8971: 8970: 8952: 8949: 8948: 8924: 8921: 8920: 8899: 8891: 8888: 8887: 8860: 8845: 8838: 8833: 8830: 8829: 8828:is realized as 8804: 8801: 8800: 8782: 8779: 8778: 8760: 8757: 8756: 8732: 8729: 8728: 8707: 8696: 8693: 8692: 8674: 8671: 8670: 8649: 8641: 8638: 8637: 8619: 8616: 8615: 8591: 8565: 8554: 8551: 8550: 8502: 8499: 8498: 8466: 8463: 8462: 8412: 8409: 8408: 8378: 8375: 8374: 8356: 8353: 8352: 8327: 8324: 8323: 8305: 8302: 8301: 8280: 8277: 8276: 8258: 8255: 8254: 8251: 8167: 8164: 8163: 8145: 8142: 8141: 8117: 8114: 8113: 8095: 8092: 8091: 8069: 8066: 8065: 8047: 8044: 8043: 7923: 7920: 7919: 7898: 7895: 7894: 7867: 7864: 7863: 7845: 7842: 7841: 7815: 7812: 7811: 7793: 7790: 7789: 7770: 7766: 7764: 7761: 7760: 7742: 7737: 7734: 7733: 7715: 7712: 7711: 7690: 7687: 7686: 7581: 7578: 7577: 7551: 7548: 7547: 7529: 7526: 7525: 7402: 7399: 7398: 7263: 7260: 7259: 7214: 7211: 7210: 7171: 7168: 7167: 7134: 7131: 7130: 7112: 7109: 7108: 7090: 7087: 7086: 7014: 7011: 7010: 6976: 6972: 6949: 6946: 6945: 6911: 6907: 6884: 6881: 6880: 6862: 6859: 6858: 6818: 6814: 6769: 6765: 6720: 6716: 6693: 6690: 6689: 6632: 6629: 6628: 6607: 6604: 6603: 6585: 6582: 6581: 6563: 6560: 6559: 6523: 6520: 6519: 6501: 6498: 6497: 6479: 6476: 6475: 6457: 6454: 6453: 6435: 6432: 6431: 6413: 6410: 6409: 6391: 6388: 6387: 6351: 6348: 6347: 6325: 6322: 6321: 6303: 6300: 6299: 6272: 6269: 6268: 6243: 6240: 6239: 6221: 6218: 6217: 6052: 6049: 6048: 6030: 6027: 6026: 6008: 6005: 6004: 5974: 5971: 5970: 5952: 5949: 5948: 5921: 5918: 5917: 5899: 5896: 5895: 5865: 5862: 5861: 5843: 5840: 5839: 5821: 5818: 5817: 5799: 5796: 5795: 5777: 5774: 5773: 5755: 5752: 5751: 5697: 5694: 5693: 5675: 5672: 5671: 5640: 5637: 5636: 5606: 5603: 5602: 5557: 5554: 5553: 5484: 5481: 5480: 5408: 5405: 5404: 5385: 5381: 5363: 5359: 5333: 5330: 5329: 5311: 5308: 5307: 5286: 5283: 5282: 5264: 5261: 5260: 5242: 5239: 5238: 5220: 5217: 5216: 5189: 5186: 5185: 5167: 5164: 5163: 5145: 5142: 5141: 5114: 5111: 5110: 5051: 5048: 5047: 5023: 5020: 5019: 5001: 4998: 4997: 4973: 4970: 4969: 4966: 4943: 4940: 4939: 4909: 4906: 4905: 4887: 4884: 4883: 4814: 4811: 4810: 4786: 4783: 4782: 4758: 4755: 4754: 4716: 4713: 4712: 4694: 4691: 4690: 4672: 4669: 4668: 4650: 4647: 4646: 4628: 4625: 4624: 4555: 4552: 4551: 4515: 4512: 4511: 4478: 4475: 4474: 4447: 4444: 4443: 4413: 4410: 4409: 4391: 4388: 4387: 4351: 4348: 4347: 4314: 4311: 4310: 4241: 4238: 4237: 4180: 4177: 4176: 4136: 4133: 4132: 4114: 4109: 4106: 4105: 4072: 4069: 4068: 4041: 4038: 4037: 4001: 3998: 3997: 3964: 3961: 3960: 3903: 3900: 3899: 3881: 3878: 3877: 3859: 3856: 3855: 3843: 3820: 3817: 3816: 3747: 3744: 3743: 3716: 3713: 3712: 3694: 3691: 3690: 3657: 3654: 3653: 3652:. For example, 3635: 3632: 3631: 3613: 3610: 3609: 3576: 3573: 3572: 3554: 3551: 3550: 3549:might take us, 3532: 3529: 3528: 3510: 3507: 3506: 3473: 3470: 3469: 3451: 3448: 3447: 3429: 3426: 3425: 3401: 3398: 3397: 3379: 3376: 3375: 3357: 3354: 3353: 3329: 3326: 3325: 3300: 3297: 3296: 3278: 3275: 3274: 3256: 3253: 3252: 3234: 3231: 3230: 3212: 3209: 3208: 3190: 3187: 3186: 3168: 3165: 3164: 3162: 3160: 3158: 3140: 3137: 3136: 3118: 3115: 3114: 3096: 3093: 3092: 3074: 3071: 3070: 3052: 3049: 3048: 3030: 3027: 3026: 3024: 3000: 2997: 2996: 2972: 2969: 2968: 2958: 2874: 2871: 2870: 2805: 2802: 2801: 2748: 2740: 2737: 2736: 2671: 2668: 2667: 2632: 2629: 2628: 2596: 2593: 2592: 2541: 2538: 2537: 2534: 2511: 2508: 2507: 2477: 2474: 2473: 2455: 2452: 2451: 2433: 2430: 2429: 2411: 2408: 2407: 2389: 2386: 2385: 2367: 2364: 2363: 2361: 2339: 2330: 2329: 2312: 2307: 2304: 2303: 2301: 2283: 2280: 2279: 2261: 2258: 2257: 2239: 2236: 2235: 2217: 2214: 2213: 2195: 2192: 2191: 2173: 2170: 2169: 2167: 2149: 2146: 2145: 2127: 2124: 2123: 2105: 2102: 2101: 2083: 2080: 2079: 2061: 2058: 2057: 2039: 2036: 2035: 2033: 2015: 2012: 2011: 2005: 1979: 1976: 1975: 1957: 1954: 1953: 1872: 1869: 1868: 1803: 1800: 1799: 1746: 1738: 1735: 1734: 1669: 1666: 1665: 1630: 1627: 1626: 1597: 1594: 1593: 1561: 1558: 1557: 1538: 1535: 1534: 1510: 1507: 1506: 1481: 1478: 1477: 1458: 1455: 1454: 1400: 1397: 1396: 1389: 1366: 1361: 1358: 1357: 1356:, definable as 1331: 1328: 1327: 1305: 1302: 1301: 1283: 1280: 1279: 1257: 1252: 1249: 1248: 1230: 1227: 1226: 1208: 1205: 1204: 1178: 1177: 1172: 1169: 1168: 1150: 1147: 1146: 1128: 1125: 1124: 1103: 1098: 1095: 1094: 1070: 1067: 1066: 1065:, also written 1038: 1035: 1034: 1016: 1013: 1012: 994: 991: 990: 978:) quantifiers. 961: 958: 957: 939: 936: 935: 887: 884: 883: 835: 832: 831: 809: 806: 805: 787: 784: 783: 765: 762: 761: 743: 740: 739: 712: 709: 708: 690: 687: 686: 668: 665: 664: 646: 643: 642: 624: 621: 620: 593: 590: 589: 561: 558: 557: 533: 530: 529: 511: 508: 507: 489: 486: 485: 466: 463: 462: 444: 441: 440: 421: 418: 417: 415:modal operators 408: 361: 344: 341: 340: 321: 319: 316: 315: 296: 293: 292: 273: 270: 269: 249: 244: 241: 240: 218: 215: 214: 195: 190: 187: 186: 153: 150: 149: 116: 113: 112: 79: 71: 60: 58: 55: 54: 21: 12: 11: 5: 10391: 10381: 10380: 10375: 10370: 10356: 10355: 10349: 10339: 10331: 10330:External links 10328: 10327: 10326: 10316: 10310: 10298: 10295: 10292: 10291: 10284: 10261: 10254: 10229: 10228: 10226: 10223: 10222: 10221: 10210: 10209: 10197: 10194: 10192: 10191: 10186: 10181: 10176: 10174:Temporal logic 10171: 10169:Kleene algebra 10166: 10160: 10158: 10155: 10143:temporal logic 10133: 10130: 10111: 10108: 10105: 10102: 10099: 10096: 10093: 10071: 10068: 10065: 10062: 10040: 10037: 10034: 10031: 10028: 10025: 10022: 10003:logical system 9988: 9985: 9982: 9979: 9976: 9973: 9951: 9948: 9945: 9942: 9939: 9919: 9916: 9869: 9866: 9863: 9860: 9857: 9846:Richard Ladner 9804: 9801: 9798: 9795: 9792: 9789: 9786: 9783: 9780: 9777: 9774: 9771: 9749: 9746: 9743: 9721: 9718: 9715: 9712: 9709: 9687: 9665: 9662: 9659: 9637: 9615: 9612: 9609: 9606: 9603: 9600: 9597: 9594: 9591: 9588: 9585: 9582: 9566: 9563: 9554:possible world 9549: 9546: 9532: 9528: 9525: 9522: 9519: 9516: 9513: 9510: 9506: 9502: 9499: 9495: 9491: 9488: 9468: 9448: 9420: 9417: 9414: 9392: 9389: 9367: 9363: 9358: 9354: 9351: 9329: 9326: 9304: 9300: 9295: 9291: 9288: 9266: 9244: 9222: 9219: 9215: 9210: 9206: 9203: 9181: 9159: 9137: 9134: 9130: 9125: 9121: 9118: 9096: 9073: 9068: 9064: 9052: 9049: 9034: 9031: 9028: 9006: 8984: 8981: 8978: 8956: 8934: 8931: 8928: 8906: 8902: 8898: 8895: 8873: 8870: 8867: 8863: 8858: 8855: 8852: 8848: 8844: 8841: 8837: 8824:The construct 8808: 8786: 8764: 8742: 8739: 8736: 8714: 8710: 8706: 8703: 8700: 8678: 8656: 8652: 8648: 8645: 8623: 8601: 8598: 8594: 8590: 8587: 8584: 8581: 8578: 8575: 8572: 8568: 8564: 8561: 8558: 8545:The construct 8530: 8527: 8524: 8521: 8518: 8515: 8512: 8509: 8506: 8479: 8476: 8473: 8470: 8446: 8443: 8440: 8437: 8434: 8431: 8428: 8425: 8422: 8419: 8416: 8385: 8382: 8360: 8334: 8331: 8309: 8287: 8284: 8262: 8250: 8247: 8228: 8225: 8222: 8219: 8216: 8213: 8210: 8207: 8204: 8201: 8198: 8195: 8192: 8189: 8186: 8183: 8180: 8177: 8174: 8171: 8149: 8127: 8124: 8121: 8099: 8088:natural number 8073: 8051: 8029: 8026: 8023: 8020: 8017: 8014: 8011: 8008: 8005: 8002: 7999: 7996: 7993: 7990: 7987: 7984: 7981: 7978: 7975: 7972: 7969: 7966: 7963: 7960: 7957: 7954: 7951: 7948: 7945: 7942: 7939: 7936: 7933: 7930: 7927: 7902: 7880: 7877: 7874: 7871: 7849: 7819: 7797: 7773: 7769: 7745: 7741: 7719: 7697: 7694: 7669: 7666: 7663: 7660: 7657: 7654: 7651: 7648: 7645: 7642: 7639: 7636: 7633: 7630: 7627: 7624: 7621: 7618: 7615: 7612: 7609: 7606: 7603: 7600: 7597: 7594: 7591: 7588: 7585: 7555: 7533: 7508: 7505: 7502: 7499: 7496: 7493: 7490: 7487: 7484: 7481: 7478: 7475: 7472: 7469: 7466: 7463: 7460: 7457: 7454: 7451: 7448: 7445: 7442: 7439: 7436: 7433: 7430: 7427: 7424: 7421: 7418: 7415: 7412: 7409: 7406: 7384: 7381: 7378: 7375: 7372: 7369: 7366: 7363: 7360: 7357: 7354: 7351: 7348: 7345: 7342: 7339: 7336: 7333: 7330: 7327: 7324: 7321: 7318: 7315: 7312: 7309: 7306: 7303: 7300: 7297: 7294: 7291: 7288: 7285: 7282: 7279: 7276: 7273: 7270: 7267: 7245: 7242: 7239: 7236: 7233: 7230: 7227: 7224: 7221: 7218: 7196: 7193: 7190: 7187: 7184: 7181: 7178: 7175: 7153: 7150: 7147: 7144: 7141: 7138: 7116: 7094: 7072: 7069: 7066: 7063: 7060: 7057: 7054: 7051: 7048: 7045: 7042: 7039: 7036: 7033: 7030: 7027: 7024: 7021: 7018: 6996: 6993: 6990: 6987: 6984: 6979: 6975: 6971: 6968: 6965: 6962: 6959: 6956: 6953: 6931: 6928: 6925: 6922: 6919: 6914: 6910: 6906: 6903: 6900: 6897: 6894: 6891: 6888: 6866: 6844: 6841: 6838: 6835: 6832: 6829: 6826: 6821: 6817: 6813: 6810: 6807: 6804: 6801: 6798: 6795: 6792: 6789: 6786: 6783: 6780: 6777: 6772: 6768: 6764: 6761: 6758: 6755: 6752: 6749: 6746: 6743: 6740: 6737: 6734: 6731: 6728: 6723: 6719: 6715: 6712: 6709: 6706: 6703: 6700: 6697: 6675: 6672: 6669: 6666: 6663: 6660: 6657: 6654: 6651: 6648: 6645: 6642: 6639: 6636: 6611: 6589: 6567: 6545: 6542: 6539: 6536: 6533: 6530: 6527: 6505: 6483: 6461: 6439: 6417: 6395: 6373: 6370: 6367: 6364: 6361: 6358: 6355: 6329: 6307: 6285: 6282: 6279: 6276: 6247: 6225: 6203: 6200: 6197: 6194: 6191: 6188: 6185: 6182: 6179: 6176: 6173: 6170: 6167: 6164: 6161: 6158: 6155: 6152: 6149: 6146: 6143: 6140: 6137: 6134: 6131: 6128: 6125: 6122: 6119: 6116: 6113: 6110: 6107: 6104: 6101: 6098: 6095: 6092: 6089: 6086: 6083: 6080: 6077: 6074: 6071: 6068: 6065: 6062: 6059: 6056: 6034: 6012: 5990: 5987: 5984: 5981: 5978: 5956: 5934: 5931: 5928: 5925: 5903: 5875: 5872: 5869: 5847: 5825: 5803: 5781: 5759: 5737: 5734: 5731: 5728: 5725: 5722: 5719: 5716: 5713: 5710: 5707: 5704: 5701: 5679: 5650: 5647: 5644: 5622: 5619: 5616: 5613: 5610: 5588: 5585: 5582: 5579: 5576: 5573: 5570: 5567: 5564: 5561: 5539: 5536: 5533: 5530: 5527: 5524: 5521: 5518: 5515: 5512: 5509: 5506: 5503: 5500: 5497: 5494: 5491: 5488: 5463: 5460: 5457: 5454: 5451: 5448: 5445: 5442: 5439: 5436: 5433: 5430: 5427: 5424: 5421: 5418: 5415: 5412: 5388: 5384: 5380: 5377: 5374: 5371: 5366: 5362: 5358: 5355: 5352: 5349: 5346: 5343: 5340: 5337: 5315: 5306:, replaced by 5293: 5290: 5268: 5246: 5224: 5202: 5199: 5196: 5193: 5171: 5149: 5127: 5124: 5121: 5118: 5094: 5091: 5088: 5085: 5082: 5079: 5076: 5073: 5070: 5067: 5064: 5061: 5058: 5055: 5027: 5005: 4983: 4980: 4977: 4965: 4962: 4947: 4925: 4922: 4919: 4916: 4913: 4891: 4869: 4866: 4863: 4860: 4857: 4854: 4851: 4848: 4845: 4842: 4839: 4836: 4833: 4830: 4827: 4824: 4821: 4818: 4796: 4793: 4790: 4768: 4765: 4762: 4732: 4729: 4726: 4723: 4720: 4698: 4676: 4654: 4632: 4610: 4607: 4604: 4601: 4598: 4595: 4592: 4589: 4586: 4583: 4580: 4577: 4574: 4571: 4568: 4565: 4562: 4559: 4534: 4531: 4528: 4525: 4522: 4519: 4497: 4494: 4491: 4488: 4485: 4482: 4460: 4457: 4454: 4451: 4429: 4426: 4423: 4420: 4417: 4408:must hold but 4395: 4373: 4370: 4367: 4364: 4361: 4358: 4355: 4333: 4330: 4327: 4324: 4321: 4318: 4296: 4293: 4290: 4287: 4284: 4281: 4278: 4275: 4272: 4269: 4266: 4263: 4260: 4257: 4254: 4251: 4248: 4245: 4223: 4220: 4217: 4214: 4211: 4208: 4205: 4202: 4199: 4196: 4193: 4190: 4187: 4184: 4175:The inference 4158: 4155: 4152: 4149: 4146: 4143: 4140: 4117: 4113: 4091: 4088: 4085: 4082: 4079: 4076: 4054: 4051: 4048: 4045: 4023: 4020: 4017: 4014: 4011: 4008: 4005: 3983: 3980: 3977: 3974: 3971: 3968: 3946: 3943: 3940: 3937: 3934: 3931: 3928: 3925: 3922: 3919: 3916: 3913: 3910: 3907: 3885: 3863: 3842: 3839: 3824: 3802: 3799: 3796: 3793: 3790: 3787: 3784: 3781: 3778: 3775: 3772: 3769: 3766: 3763: 3760: 3757: 3754: 3751: 3729: 3726: 3723: 3720: 3698: 3676: 3673: 3670: 3667: 3664: 3661: 3639: 3617: 3595: 3592: 3589: 3586: 3583: 3580: 3558: 3536: 3514: 3492: 3489: 3486: 3483: 3480: 3477: 3455: 3433: 3411: 3408: 3405: 3383: 3361: 3339: 3336: 3333: 3304: 3282: 3260: 3238: 3216: 3194: 3185:by performing 3172: 3144: 3122: 3100: 3091:, then either 3078: 3056: 3034: 3010: 3007: 3004: 2982: 2979: 2976: 2938: 2935: 2932: 2929: 2926: 2923: 2920: 2917: 2914: 2911: 2908: 2905: 2902: 2899: 2896: 2893: 2890: 2887: 2884: 2881: 2878: 2854: 2851: 2848: 2845: 2842: 2839: 2836: 2833: 2830: 2827: 2824: 2821: 2818: 2815: 2812: 2809: 2785: 2782: 2779: 2776: 2773: 2770: 2767: 2764: 2761: 2758: 2755: 2751: 2747: 2744: 2720: 2717: 2714: 2711: 2708: 2705: 2702: 2699: 2696: 2693: 2690: 2687: 2684: 2681: 2678: 2675: 2651: 2648: 2645: 2642: 2639: 2636: 2612: 2609: 2606: 2603: 2600: 2575: 2572: 2569: 2566: 2563: 2560: 2557: 2554: 2551: 2548: 2545: 2533: 2530: 2515: 2481: 2459: 2437: 2415: 2393: 2371: 2358:Kleene algebra 2342: 2338: 2333: 2328: 2325: 2322: 2319: 2315: 2311: 2287: 2265: 2243: 2221: 2199: 2177: 2153: 2131: 2109: 2087: 2065: 2043: 2019: 1983: 1961: 1933: 1930: 1927: 1924: 1921: 1918: 1915: 1912: 1909: 1906: 1903: 1900: 1897: 1894: 1891: 1888: 1885: 1882: 1879: 1876: 1852: 1849: 1846: 1843: 1840: 1837: 1834: 1831: 1828: 1825: 1822: 1819: 1816: 1813: 1810: 1807: 1783: 1780: 1777: 1774: 1771: 1768: 1765: 1762: 1759: 1756: 1753: 1749: 1745: 1742: 1718: 1715: 1712: 1709: 1706: 1703: 1700: 1697: 1694: 1691: 1688: 1685: 1682: 1679: 1676: 1673: 1649: 1646: 1643: 1640: 1637: 1634: 1610: 1607: 1604: 1601: 1577: 1574: 1571: 1568: 1565: 1545: 1542: 1517: 1514: 1494: 1491: 1488: 1485: 1465: 1462: 1434: 1431: 1428: 1425: 1422: 1419: 1416: 1413: 1410: 1407: 1404: 1388: 1385: 1369: 1365: 1335: 1309: 1287: 1260: 1256: 1234: 1212: 1186: 1181: 1176: 1154: 1132: 1110: 1106: 1102: 1080: 1077: 1074: 1048: 1045: 1042: 1020: 998: 965: 943: 921: 918: 915: 912: 909: 906: 903: 900: 897: 894: 891: 869: 866: 863: 860: 857: 854: 851: 848: 845: 842: 839: 813: 791: 769: 747: 725: 722: 719: 716: 694: 672: 650: 628: 606: 603: 600: 597: 571: 568: 565: 543: 540: 537: 515: 493: 473: 470: 448: 428: 425: 407: 404: 367: 364: 360: 357: 354: 351: 348: 327: 324: 300: 277: 252: 248: 228: 225: 222: 202: 198: 194: 166: 163: 160: 157: 129: 126: 123: 120: 98: 97: 86: 78: 70: 67: 9: 6: 4: 3: 2: 10390: 10379: 10376: 10374: 10371: 10369: 10366: 10365: 10363: 10353: 10350: 10347: 10343: 10340: 10337: 10334: 10333: 10324: 10320: 10317: 10314: 10311: 10308: 10304: 10303:Vaughan Pratt 10301: 10300: 10287: 10281: 10274: 10273: 10265: 10257: 10251: 10247: 10243: 10242: 10234: 10230: 10219: 10216: 10212: 10211: 10207: 10203: 10200: 10199: 10190: 10187: 10185: 10182: 10180: 10177: 10175: 10172: 10170: 10167: 10165: 10162: 10161: 10154: 10152: 10148: 10144: 10140: 10129: 10127: 10106: 10103: 10100: 10094: 10091: 10069: 10063: 10035: 10032: 10029: 10023: 10020: 10012: 10008: 10004: 9986: 9980: 9971: 9949: 9943: 9937: 9929: 9925: 9924:Vaughan Pratt 9915: 9913: 9909: 9905: 9900: 9899:Vaughan Pratt 9896: 9892: 9888: 9883: 9867: 9864: 9861: 9858: 9855: 9847: 9843: 9838: 9836: 9832: 9828: 9824: 9820: 9799: 9796: 9793: 9784: 9781: 9778: 9775: 9772: 9747: 9744: 9741: 9719: 9716: 9713: 9710: 9707: 9685: 9663: 9660: 9657: 9635: 9610: 9607: 9604: 9595: 9592: 9589: 9586: 9583: 9572: 9562: 9560: 9555: 9545: 9530: 9523: 9520: 9517: 9514: 9511: 9504: 9497: 9493: 9489: 9466: 9446: 9438: 9434: 9418: 9415: 9412: 9390: 9361: 9356: 9352: 9327: 9298: 9293: 9289: 9264: 9242: 9220: 9213: 9208: 9204: 9179: 9157: 9135: 9128: 9123: 9119: 9094: 9071: 9066: 9062: 9048: 9032: 9029: 9004: 8982: 8979: 8954: 8947:. As long as 8932: 8929: 8904: 8900: 8896: 8893: 8871: 8868: 8861: 8856: 8850: 8846: 8842: 8839: 8827: 8822: 8806: 8784: 8777:. Hence when 8762: 8740: 8737: 8734: 8712: 8708: 8704: 8701: 8676: 8654: 8650: 8646: 8643: 8621: 8596: 8592: 8588: 8585: 8576: 8570: 8566: 8562: 8559: 8548: 8543: 8528: 8525: 8522: 8516: 8510: 8507: 8497: 8493: 8474: 8471: 8459: 8441: 8435: 8426: 8420: 8417: 8407: 8403: 8401: 8383: 8380: 8358: 8350: 8332: 8329: 8307: 8285: 8282: 8260: 8246: 8244: 8226: 8220: 8217: 8205: 8199: 8190: 8181: 8178: 8172: 8169: 8147: 8125: 8122: 8119: 8097: 8089: 8071: 8049: 8024: 8021: 8018: 8009: 7991: 7988: 7985: 7982: 7979: 7964: 7961: 7958: 7946: 7940: 7934: 7917: 7900: 7875: 7847: 7839: 7835: 7817: 7795: 7771: 7767: 7743: 7739: 7717: 7695: 7683: 7664: 7655: 7637: 7634: 7631: 7616: 7604: 7598: 7592: 7575: 7571: 7553: 7531: 7522: 7503: 7500: 7497: 7488: 7470: 7467: 7464: 7461: 7458: 7443: 7440: 7437: 7425: 7419: 7413: 7379: 7376: 7373: 7364: 7346: 7343: 7340: 7328: 7325: 7322: 7319: 7316: 7304: 7301: 7298: 7286: 7280: 7274: 7240: 7234: 7231: 7228: 7225: 7222: 7191: 7188: 7185: 7176: 7148: 7145: 7142: 7114: 7092: 7067: 7058: 7052: 7049: 7046: 7043: 7040: 7031: 7028: 7025: 7022: 7019: 6991: 6977: 6969: 6966: 6963: 6960: 6957: 6926: 6912: 6904: 6901: 6898: 6895: 6892: 6864: 6842: 6839: 6833: 6819: 6811: 6808: 6805: 6802: 6799: 6790: 6784: 6770: 6762: 6759: 6756: 6753: 6750: 6741: 6735: 6721: 6713: 6710: 6707: 6704: 6701: 6670: 6658: 6652: 6649: 6646: 6643: 6640: 6625: 6609: 6587: 6565: 6540: 6537: 6534: 6531: 6528: 6503: 6481: 6459: 6437: 6415: 6393: 6368: 6365: 6362: 6359: 6356: 6345: 6327: 6305: 6280: 6265: 6263: 6245: 6223: 6198: 6186: 6180: 6177: 6174: 6171: 6168: 6147: 6135: 6132: 6129: 6126: 6123: 6111: 6096: 6090: 6087: 6084: 6081: 6078: 6069: 6063: 6032: 6010: 5988: 5985: 5982: 5979: 5976: 5954: 5947:, the action 5929: 5901: 5893: 5889: 5873: 5870: 5867: 5845: 5823: 5801: 5779: 5757: 5735: 5732: 5729: 5723: 5717: 5714: 5711: 5708: 5705: 5677: 5668: 5666: 5648: 5645: 5642: 5620: 5617: 5614: 5611: 5608: 5586: 5583: 5580: 5574: 5571: 5568: 5565: 5562: 5537: 5534: 5531: 5528: 5525: 5516: 5513: 5510: 5501: 5498: 5495: 5492: 5489: 5479:The instance 5477: 5461: 5458: 5455: 5452: 5449: 5440: 5437: 5434: 5431: 5428: 5419: 5416: 5413: 5386: 5382: 5378: 5375: 5364: 5360: 5356: 5353: 5344: 5341: 5338: 5313: 5291: 5244: 5197: 5169: 5122: 5107: 5089: 5074: 5062: 5059: 5056: 5046: 5042: 5025: 5003: 4981: 4978: 4975: 4961: 4945: 4923: 4920: 4917: 4914: 4911: 4889: 4864: 4861: 4858: 4849: 4846: 4843: 4840: 4837: 4825: 4822: 4819: 4791: 4763: 4752: 4748: 4730: 4727: 4724: 4721: 4718: 4696: 4674: 4652: 4630: 4605: 4602: 4599: 4590: 4587: 4584: 4581: 4578: 4566: 4563: 4560: 4548: 4532: 4526: 4517: 4495: 4489: 4480: 4458: 4452: 4427: 4421: 4418: 4393: 4371: 4365: 4362: 4353: 4331: 4325: 4316: 4291: 4285: 4282: 4273: 4261: 4255: 4246: 4221: 4215: 4212: 4203: 4200: 4197: 4191: 4182: 4173: 4156: 4150: 4147: 4138: 4115: 4111: 4089: 4083: 4074: 4052: 4046: 4021: 4015: 4012: 4003: 3981: 3975: 3966: 3944: 3938: 3935: 3926: 3923: 3920: 3914: 3905: 3883: 3861: 3852: 3851:necessitation 3848: 3838: 3822: 3797: 3794: 3791: 3782: 3779: 3776: 3773: 3770: 3758: 3755: 3752: 3727: 3721: 3696: 3674: 3668: 3659: 3637: 3615: 3593: 3587: 3578: 3556: 3534: 3512: 3490: 3484: 3478: 3475: 3453: 3431: 3409: 3406: 3403: 3381: 3359: 3337: 3331: 3322: 3318: 3302: 3280: 3258: 3236: 3214: 3192: 3170: 3142: 3120: 3098: 3076: 3054: 3032: 3005: 2977: 2966: 2962: 2956: 2951: 2933: 2927: 2921: 2918: 2906: 2903: 2897: 2894: 2888: 2882: 2879: 2867: 2852: 2846: 2843: 2834: 2828: 2825: 2819: 2813: 2810: 2798: 2783: 2777: 2768: 2759: 2753: 2749: 2745: 2733: 2718: 2712: 2706: 2703: 2697: 2688: 2682: 2679: 2676: 2664: 2649: 2643: 2637: 2625: 2610: 2604: 2589: 2573: 2564: 2552: 2546: 2529: 2513: 2505: 2501: 2500:n := n+1 2497: 2479: 2457: 2435: 2413: 2391: 2369: 2359: 2340: 2336: 2331: 2326: 2323: 2320: 2317: 2313: 2309: 2285: 2263: 2241: 2219: 2197: 2175: 2151: 2129: 2107: 2085: 2063: 2041: 2017: 2009: 2006:A2 says that 2003: 1999: 1981: 1959: 1951: 1946: 1931: 1925: 1922: 1910: 1904: 1895: 1886: 1883: 1877: 1874: 1865: 1850: 1844: 1841: 1832: 1826: 1823: 1817: 1811: 1808: 1796: 1781: 1775: 1766: 1757: 1751: 1747: 1743: 1731: 1716: 1710: 1704: 1701: 1695: 1686: 1680: 1677: 1674: 1662: 1647: 1641: 1635: 1623: 1608: 1602: 1590: 1575: 1569: 1563: 1543: 1540: 1532: 1531:necessitation 1515: 1512: 1492: 1486: 1483: 1463: 1460: 1452: 1451: 1432: 1423: 1411: 1405: 1394: 1384: 1367: 1363: 1355: 1351: 1333: 1325: 1307: 1285: 1277: 1258: 1254: 1232: 1210: 1202: 1184: 1179: 1174: 1152: 1130: 1108: 1100: 1078: 1075: 1072: 1064: 1046: 1043: 1040: 1018: 996: 988: 984: 979: 919: 910: 898: 892: 867: 858: 846: 840: 829: 811: 789: 767: 745: 723: 717: 692: 670: 648: 626: 604: 598: 587: 566: 538: 513: 491: 471: 468: 446: 426: 423: 416: 412: 403: 401: 397: 393: 389: 384: 382: 365: 362: 355: 346: 325: 322: 314: 313:postcondition 298: 291: 275: 267: 250: 246: 226: 223: 220: 200: 196: 192: 184: 180: 164: 158: 147: 143: 127: 121: 110: 106: 101: 84: 53: 52: 51: 48: 46: 42: 38: 37:dynamic logic 34: 30: 26: 19: 10345: 10323:Dexter Kozen 10271: 10264: 10240: 10233: 10206:Dexter Kozen 10135: 9921: 9884: 9839: 9834: 9830: 9826: 9569:Ordinary or 9568: 9551: 9435: 9054: 8826:while p do a 8825: 8823: 8546: 8544: 8495: 8494: 8460: 8405: 8404: 8399: 8348: 8252: 8242: 8087: 7915: 7837: 7833: 7684: 7523: 6626: 6266: 6261: 5890: 5669: 5478: 5108: 5044: 5043: 4967: 4750: 4746: 4549: 4174: 3850: 3847:modus ponens 3846: 3844: 3323: 3319: 2964: 2960: 2954: 2952: 2868: 2799: 2734: 2665: 2626: 2590: 2535: 2503: 2499: 2032:into itself. 2007: 2001: 1997: 1952:terminates, 1949: 1947: 1866: 1797: 1732: 1663: 1624: 1591: 1530: 1450:modus ponens 1448: 1390: 1353: 1349: 1323: 1275: 1200: 1062: 980: 409: 385: 290:precondition 182: 178: 145: 141: 108: 105:propositions 104: 102: 99: 49: 36: 22: 10368:Modal logic 10319:David Harel 10313:David Harel 10202:David Harel 10164:Hoare logic 10139:Amir Pnueli 9928:Hoare logic 8636:holds then 8086:is of type 2532:Derivations 1393:modal logic 411:Modal logic 392:linguistics 381:Hoare logic 41:modal logic 10362:Categories 10297:References 10285:8301068590 10255:013215871X 9700:are data, 9194:to, while 8691:, whereas 8373:is false, 8347:acts as a 8275:an action 8245:be false. 7836:, or even 7572:to obtain 5403:, or with 4964:Assignment 4346:holds but 396:philosophy 29:philosophy 10225:Footnotes 10095:⁡ 10024:⁡ 9975:→ 9797:≥ 9745:≥ 9608:≥ 9531:∗ 9388:∃ 9366:⟩ 9350:⟨ 9325:∀ 9218:⟩ 9202:⟨ 9027:¬ 8977:¬ 8927:¬ 8866:¬ 8857:∗ 8738:∪ 8699:¬ 8583:¬ 8577:∪ 8526:∧ 8520:↔ 8514:⟩ 8505:⟨ 8478:⟩ 8469:⟨ 8439:→ 8430:↔ 8221:∗ 8212:↔ 8194:→ 8182:∗ 8173:∧ 8013:Φ 8007:∀ 8004:→ 7974:Φ 7971:→ 7953:Φ 7944:∀ 7941:∧ 7929:Φ 7870:Φ 7744:∗ 7693:∀ 7659:Φ 7653:∀ 7650:→ 7626:Φ 7623:→ 7611:Φ 7602:∀ 7599:∧ 7587:Φ 7492:Φ 7486:∀ 7483:→ 7453:Φ 7450:→ 7432:Φ 7423:∀ 7420:∧ 7408:Φ 7368:Φ 7362:∀ 7359:→ 7335:Φ 7311:→ 7293:Φ 7284:∀ 7281:∧ 7269:Φ 7241:∗ 7180:Φ 7174:∀ 7137:Φ 7085:, having 7062:Φ 7059:… 6986:Φ 6921:Φ 6843:… 6840:∧ 6828:Φ 6791:∧ 6779:Φ 6742:∧ 6730:Φ 6665:Φ 6659:∗ 6275:Φ 6193:Φ 6187:∗ 6160:→ 6142:Φ 6118:→ 6106:Φ 6097:∗ 6070:∧ 6058:Φ 5924:Φ 5871:≤ 5727:⟩ 5724:∗ 5700:⟨ 5678:∗ 5646:≥ 5618:≥ 5584:≥ 5535:≥ 5523:↔ 5514:≥ 5447:↔ 5373:↔ 5289:∀ 5267:Φ 5223:Φ 5192:Φ 5148:Φ 5117:Φ 5084:Φ 5081:↔ 5069:Φ 4862:≥ 4853:⟩ 4835:⟨ 4832:→ 4823:≥ 4795:⟩ 4789:⟨ 4603:≥ 4573:→ 4564:≥ 4521:→ 4484:→ 4422:∗ 4366:∗ 4357:→ 4320:→ 4286:∗ 4277:→ 4268:→ 4250:→ 4216:∗ 4207:→ 4201:⊢ 4186:→ 4151:∗ 4142:→ 4116:∗ 4078:→ 4016:∗ 4007:→ 3970:→ 3939:∗ 3930:→ 3924:⊢ 3909:→ 3765:→ 3663:→ 3582:→ 3479:⊢ 3407:⊢ 3335:→ 3009:⟩ 3003:⟨ 2931:⟩ 2925:⟨ 2922:∧ 2916:¬ 2910:⟩ 2907:∗ 2901:⟨ 2898:∨ 2892:→ 2886:⟩ 2883:∗ 2877:⟨ 2850:⟩ 2847:∗ 2841:⟨ 2838:⟩ 2832:⟨ 2829:∨ 2823:↔ 2817:⟩ 2814:∗ 2808:⟨ 2781:⟩ 2775:⟨ 2772:⟩ 2766:⟨ 2763:↔ 2757:⟩ 2743:⟨ 2716:⟩ 2710:⟨ 2707:∨ 2701:⟩ 2695:⟨ 2692:↔ 2686:⟩ 2680:∪ 2674:⟨ 2647:↔ 2641:⟩ 2635:⟨ 2608:⟩ 2602:⟨ 2599:¬ 2571:¬ 2568:⟩ 2562:⟨ 2559:¬ 2556:↔ 2341:∗ 2324:∪ 2314:∗ 2190:and then 2000:. (Thus 1926:∗ 1917:→ 1899:→ 1887:∗ 1878:∧ 1845:∗ 1827:∧ 1821:↔ 1812:∗ 1761:↔ 1705:∧ 1690:↔ 1678:∪ 1645:↔ 1564:⊢ 1541:⊢ 1513:⊢ 1490:→ 1484:⊢ 1461:⊢ 1430:¬ 1427:⟩ 1421:⟨ 1418:¬ 1415:↔ 1368:∗ 1276:iteration 1259:∗ 1225:and then 1044:∪ 964:∃ 942:∀ 917:¬ 905:¬ 902:↔ 896:⟩ 890:⟨ 865:¬ 862:⟩ 856:⟨ 853:¬ 850:↔ 721:⟩ 715:⟨ 570:⟩ 564:⟨ 469:◊ 424:◻ 363:φ 350:→ 347:φ 323:φ 299:φ 251:∗ 224:∪ 162:⟩ 156:⟨ 66:→ 10157:See also 10151:livelock 10147:deadlock 9889:at most 9437:Dijkstra 9342:, while 8398:acts as 1556:implies 1505:implies 1201:sequence 406:Language 366:′ 326:′ 73:It rains 10220:, 2007. 10053:, with 9918:History 7834:integer 2450:, then 2234:, then 2100:, then 109:actions 10282:  10252:  9908:Parikh 9904:Gabbay 9833:, and 9678:, and 9279:true. 6003:, and 4996:where 1529:) and 1387:Axioms 1063:choice 983:Kleene 311:, and 31:, and 10276:(PDF) 9912:Kozen 8400:BLOCK 7574:Peano 7009:into 6342:as a 4751:might 2955:BLOCK 2869:T6. 2800:T5. 2735:T4. 2666:T3. 2627:T2. 2591:T1. 2002:BLOCK 1998:false 1950:BLOCK 1867:A6. 1798:A5. 1733:A4. 1664:A3. 1625:A2. 1592:A1. 1324:BLOCK 25:logic 10348:site 10280:ISBN 10250:ISBN 10009:and 9844:and 9762:and 8492:is: 8249:Test 8243:must 7838:real 7546:for 6602:for 6298:for 6238:for 4781:and 4749:and 4747:must 3849:and 2995:and 1476:and 1350:SKIP 1011:and 882:and 828:dual 556:and 10344:at 10246:221 10092:wlp 9964:as 9835:not 9827:and 8496:T8. 8406:A8. 8349:NOP 6879:of 6025:as 5969:as 5663:by 5215:is 5045:A7. 3113:or 3047:or 2965:NOP 2961:NOP 2356:of 2056:or 2008:NOP 1589:). 1354:NOP 1352:or 1348:or 1322:or 1145:or 1093:or 985:'s 23:In 10364:: 10321:, 10248:. 10204:, 10149:, 10021:wp 9859::= 9837:. 9831:or 9829:, 9776::= 9711::= 9650:, 9587::= 9515::= 9494::= 9433:. 9416::= 9357::= 9294::= 9209::= 9124::= 9067::= 9047:. 7521:. 7320::= 7226::= 7044::= 7023::= 6961::= 6896::= 6803::= 6754::= 6705::= 6644::= 6532::= 6360::= 6172::= 6127::= 6082::= 5980::= 5888:. 5709::= 5667:. 5566::= 5493::= 5417::= 5342::= 5060::= 4979::= 4938:, 4915::= 4841::= 4745:, 4722::= 4667:, 4582::= 3774::= 3317:. 2528:. 1274:, 1199:, 1061:, 400:AI 398:, 394:, 383:. 288:, 47:. 35:, 27:, 10288:. 10258:. 10110:) 10107:p 10104:, 10101:a 10098:( 10070:p 10067:] 10064:a 10061:[ 10039:) 10036:p 10033:, 10030:a 10027:( 9987:q 9984:] 9981:a 9978:[ 9972:p 9950:q 9947:} 9944:a 9941:{ 9938:p 9868:1 9865:+ 9862:x 9856:x 9803:) 9800:4 9794:x 9791:( 9788:] 9785:1 9782:+ 9779:x 9773:x 9770:[ 9748:4 9742:x 9720:1 9717:+ 9714:x 9708:x 9686:4 9664:1 9661:+ 9658:x 9636:x 9614:) 9611:4 9605:x 9602:( 9599:] 9596:1 9593:+ 9590:x 9584:x 9581:[ 9527:) 9524:1 9521:+ 9518:x 9512:x 9509:( 9505:; 9501:) 9498:0 9490:x 9487:( 9467:x 9447:x 9419:? 9413:x 9391:x 9362:? 9353:x 9328:x 9303:] 9299:? 9290:x 9287:[ 9265:p 9243:x 9221:p 9214:? 9205:x 9180:x 9158:p 9136:p 9133:] 9129:? 9120:x 9117:[ 9095:x 9072:? 9063:x 9033:? 9030:p 9005:p 8983:? 8980:p 8955:p 8933:? 8930:p 8905:a 8901:; 8897:? 8894:p 8872:? 8869:p 8862:; 8854:) 8851:a 8847:; 8843:? 8840:p 8836:( 8807:p 8785:p 8763:a 8741:0 8735:a 8713:b 8709:; 8705:? 8702:p 8677:a 8655:a 8651:; 8647:? 8644:p 8622:p 8600:) 8597:b 8593:; 8589:? 8586:p 8580:( 8574:) 8571:a 8567:; 8563:? 8560:p 8557:( 8529:q 8523:p 8517:q 8511:? 8508:p 8475:? 8472:p 8445:) 8442:q 8436:p 8433:( 8427:q 8424:] 8421:? 8418:p 8415:[ 8384:? 8381:p 8359:p 8333:? 8330:p 8308:p 8286:? 8283:p 8261:p 8227:p 8224:] 8218:a 8215:[ 8209:) 8206:p 8203:] 8200:a 8197:[ 8191:p 8188:( 8185:] 8179:a 8176:[ 8170:p 8148:n 8126:i 8123:+ 8120:n 8098:n 8072:n 8050:n 8028:) 8025:i 8022:+ 8019:n 8016:( 8010:i 8001:) 7998:) 7995:) 7992:1 7989:+ 7986:i 7983:+ 7980:n 7977:( 7968:) 7965:i 7962:+ 7959:n 7956:( 7950:( 7947:i 7938:) 7935:n 7932:( 7926:( 7901:n 7879:) 7876:n 7873:( 7848:n 7818:n 7796:i 7772:i 7768:a 7740:a 7718:i 7696:i 7668:) 7665:i 7662:( 7656:i 7647:) 7644:) 7641:) 7638:1 7635:+ 7632:i 7629:( 7620:) 7617:i 7614:( 7608:( 7605:i 7596:) 7593:0 7590:( 7584:( 7554:n 7532:0 7507:) 7504:i 7501:+ 7498:n 7495:( 7489:i 7480:) 7477:) 7474:) 7471:1 7468:+ 7465:i 7462:+ 7459:n 7456:( 7447:) 7444:i 7441:+ 7438:n 7435:( 7429:( 7426:i 7417:) 7414:n 7411:( 7405:( 7383:) 7380:i 7377:+ 7374:n 7371:( 7365:i 7356:) 7353:) 7350:) 7347:i 7344:+ 7341:n 7338:( 7332:] 7329:1 7326:+ 7323:n 7317:n 7314:[ 7308:) 7305:i 7302:+ 7299:n 7296:( 7290:( 7287:i 7278:) 7275:n 7272:( 7266:( 7244:] 7238:) 7235:1 7232:+ 7229:n 7223:n 7220:( 7217:[ 7195:) 7192:i 7189:+ 7186:n 7183:( 7177:i 7152:) 7149:i 7146:+ 7143:n 7140:( 7115:i 7093:i 7071:) 7068:n 7065:( 7056:] 7053:1 7050:+ 7047:n 7041:n 7038:[ 7035:] 7032:1 7029:+ 7026:n 7020:n 7017:[ 6995:) 6992:n 6989:( 6983:] 6978:i 6974:) 6970:1 6967:+ 6964:n 6958:n 6955:( 6952:[ 6930:) 6927:n 6924:( 6918:] 6913:i 6909:) 6905:1 6902:+ 6899:n 6893:n 6890:( 6887:[ 6865:i 6837:) 6834:n 6831:( 6825:] 6820:2 6816:) 6812:1 6809:+ 6806:n 6800:n 6797:( 6794:[ 6788:) 6785:n 6782:( 6776:] 6771:1 6767:) 6763:1 6760:+ 6757:n 6751:n 6748:( 6745:[ 6739:) 6736:n 6733:( 6727:] 6722:0 6718:) 6714:1 6711:+ 6708:n 6702:n 6699:( 6696:[ 6674:) 6671:n 6668:( 6662:] 6656:) 6653:1 6650:+ 6647:n 6641:n 6638:( 6635:[ 6610:n 6588:0 6566:n 6544:] 6541:1 6538:+ 6535:n 6529:n 6526:[ 6504:n 6482:n 6460:n 6438:a 6416:n 6394:n 6372:] 6369:1 6366:+ 6363:n 6357:n 6354:[ 6328:p 6306:p 6284:) 6281:n 6278:( 6246:n 6224:0 6202:) 6199:n 6196:( 6190:] 6184:) 6181:1 6178:+ 6175:n 6169:n 6166:( 6163:[ 6157:) 6154:) 6151:) 6148:n 6145:( 6139:] 6136:1 6133:+ 6130:n 6124:n 6121:[ 6115:) 6112:n 6109:( 6103:( 6100:] 6094:) 6091:1 6088:+ 6085:n 6079:n 6076:( 6073:[ 6067:) 6064:n 6061:( 6055:( 6033:0 6011:n 5989:1 5986:+ 5983:n 5977:n 5955:a 5933:) 5930:n 5927:( 5902:p 5874:7 5868:x 5846:x 5824:x 5802:x 5780:x 5758:x 5736:7 5733:= 5730:x 5721:) 5718:1 5715:+ 5712:x 5706:x 5703:( 5649:3 5643:x 5621:4 5615:1 5612:+ 5609:x 5587:4 5581:x 5578:] 5575:1 5572:+ 5569:x 5563:x 5560:[ 5538:4 5532:1 5529:+ 5526:x 5520:) 5517:4 5511:x 5508:( 5505:] 5502:1 5499:+ 5496:x 5490:x 5487:[ 5462:e 5459:+ 5456:c 5453:= 5450:b 5444:) 5441:x 5438:+ 5435:c 5432:= 5429:b 5426:( 5423:] 5420:e 5414:x 5411:[ 5387:2 5383:y 5379:= 5376:e 5370:) 5365:2 5361:y 5357:= 5354:x 5351:( 5348:] 5345:e 5339:x 5336:[ 5314:e 5292:x 5245:x 5201:) 5198:e 5195:( 5170:x 5126:) 5123:x 5120:( 5093:) 5090:e 5087:( 5078:) 5075:x 5072:( 5066:] 5063:e 5057:x 5054:[ 5026:e 5004:x 4982:e 4976:x 4946:x 4924:1 4921:+ 4918:x 4912:x 4890:x 4868:) 4865:4 4859:x 4856:( 4850:1 4847:+ 4844:x 4838:x 4829:) 4826:3 4820:x 4817:( 4792:a 4767:] 4764:a 4761:[ 4731:1 4728:+ 4725:x 4719:x 4697:a 4675:x 4653:x 4631:x 4609:) 4606:4 4600:x 4597:( 4594:] 4591:1 4588:+ 4585:x 4579:x 4576:[ 4570:) 4567:3 4561:x 4558:( 4533:b 4530:] 4527:k 4524:[ 4518:b 4496:b 4493:] 4490:k 4487:[ 4481:b 4459:b 4456:] 4453:k 4450:[ 4428:b 4425:] 4419:k 4416:[ 4394:b 4372:b 4369:] 4363:k 4360:[ 4354:b 4332:b 4329:] 4326:k 4323:[ 4317:b 4295:) 4292:b 4289:] 4283:k 4280:[ 4274:b 4271:( 4265:) 4262:b 4259:] 4256:k 4253:[ 4247:b 4244:( 4222:b 4219:] 4213:k 4210:[ 4204:b 4198:b 4195:] 4192:k 4189:[ 4183:b 4157:b 4154:] 4148:k 4145:[ 4139:b 4112:k 4090:b 4087:] 4084:k 4081:[ 4075:b 4053:b 4050:] 4047:k 4044:[ 4022:b 4019:] 4013:k 4010:[ 4004:b 3982:b 3979:] 3976:k 3973:[ 3967:b 3945:b 3942:] 3936:k 3933:[ 3927:b 3921:b 3918:] 3915:k 3912:[ 3906:b 3884:b 3862:k 3823:x 3801:) 3798:1 3795:= 3792:x 3789:( 3786:] 3783:1 3780:+ 3777:x 3771:x 3768:[ 3762:) 3759:1 3756:= 3753:x 3750:( 3728:p 3725:] 3722:a 3719:[ 3697:p 3675:p 3672:] 3669:a 3666:[ 3660:p 3638:a 3616:p 3594:p 3591:] 3588:a 3585:[ 3579:p 3557:p 3535:a 3513:p 3491:p 3488:] 3485:a 3482:[ 3476:p 3454:q 3432:p 3410:q 3404:p 3382:q 3360:p 3338:q 3332:p 3303:p 3281:a 3259:p 3237:a 3215:p 3193:a 3171:p 3157:. 3143:p 3121:b 3099:a 3077:p 3055:b 3033:a 3006:1 2981:] 2978:1 2975:[ 2957:. 2937:) 2934:p 2928:a 2919:p 2913:( 2904:a 2895:p 2889:p 2880:a 2853:p 2844:a 2835:a 2826:p 2820:p 2811:a 2784:p 2778:b 2769:a 2760:p 2754:b 2750:; 2746:a 2719:p 2713:b 2704:p 2698:a 2689:p 2683:b 2677:a 2650:p 2644:p 2638:1 2611:p 2605:0 2574:p 2565:a 2553:p 2550:] 2547:a 2544:[ 2514:a 2504:n 2480:a 2458:p 2436:a 2414:p 2392:a 2370:p 2360:. 2337:a 2332:; 2327:a 2321:1 2318:= 2310:a 2300:. 2286:p 2264:b 2242:a 2220:p 2198:b 2176:a 2152:b 2130:p 2108:a 2086:p 2064:b 2042:a 2018:p 1982:p 1960:p 1932:p 1929:] 1923:a 1920:[ 1914:) 1911:p 1908:] 1905:a 1902:[ 1896:p 1893:( 1890:] 1884:a 1881:[ 1875:p 1851:p 1848:] 1842:a 1839:[ 1836:] 1833:a 1830:[ 1824:p 1818:p 1815:] 1809:a 1806:[ 1782:p 1779:] 1776:b 1773:[ 1770:] 1767:a 1764:[ 1758:p 1755:] 1752:b 1748:; 1744:a 1741:[ 1717:p 1714:] 1711:b 1708:[ 1702:p 1699:] 1696:a 1693:[ 1687:p 1684:] 1681:b 1675:a 1672:[ 1648:p 1642:p 1639:] 1636:1 1633:[ 1609:p 1606:] 1603:0 1600:[ 1576:p 1573:] 1570:a 1567:[ 1544:p 1533:( 1516:q 1493:q 1487:p 1464:p 1453:( 1433:p 1424:a 1412:p 1409:] 1406:a 1403:[ 1364:0 1334:1 1308:0 1286:a 1255:a 1233:b 1211:a 1185:b 1180:; 1175:a 1153:b 1131:a 1109:b 1105:| 1101:a 1079:b 1076:+ 1073:a 1047:b 1041:a 1019:b 997:a 920:p 914:] 911:a 908:[ 899:p 893:a 868:p 859:a 847:p 844:] 841:a 838:[ 812:p 790:a 768:p 746:a 724:p 718:a 693:p 671:a 649:p 627:a 605:p 602:] 599:a 596:[ 567:a 542:] 539:a 536:[ 514:a 492:p 472:p 447:p 427:p 359:] 356:P 353:[ 276:P 247:a 227:b 221:a 201:b 197:; 193:a 183:p 179:a 165:p 159:a 146:p 142:a 128:p 125:] 122:a 119:[ 85:, 77:] 69:[ 20:.

Index

dynamic logic (digital electronics)
logic
philosophy
theoretical computer science
modal logic
computer programs
Boolean operations
precondition
postcondition
Hoare logic
formal verification
linguistics
philosophy
AI
Modal logic
modal operators
multimodal logic
dual
Kleene
regular expression
modal logic
modus ponens
Kleene algebra
mathematical induction
elementary algebra
Mathematical induction
rigid designator
first-order logic
Peano
Dijkstra

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