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Field extension

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2118: 2431: 1856: 2189: 2113:{\displaystyle {\begin{aligned}\mathbb {Q} \left({\sqrt {2}},{\sqrt {3}}\right)&=\mathbb {Q} \left({\sqrt {2}}\right)\left({\sqrt {3}}\right)\\&=\left\{a+b{\sqrt {3}}\mid a,b\in \mathbb {Q} \left({\sqrt {2}}\right)\right\}\\&=\left\{a+b{\sqrt {2}}+c{\sqrt {3}}+d{\sqrt {6}}\mid a,b,c,d\in \mathbb {Q} \right\},\end{aligned}}} 2426:{\displaystyle {\begin{aligned}\mathbb {Q} ({\sqrt {2}},{\sqrt {3}})&=\mathbb {Q} ({\sqrt {2}}+{\sqrt {3}})\\&=\left\{a+b({\sqrt {2}}+{\sqrt {3}})+c({\sqrt {2}}+{\sqrt {3}})^{2}+d({\sqrt {2}}+{\sqrt {3}})^{3}\mid a,b,c,d\in \mathbb {Q} \right\}.\end{aligned}}} 5145:. Extension of scalars of polynomials is often used implicitly, by just considering the coefficients as being elements of a larger field, but may also be considered more formally. Extension of scalars has numerous applications, as discussed in 1777: 1331:
It is often desirable to talk about field extensions in situations where the small field is not actually contained in the larger one, but is naturally embedded. For this purpose, one abstractly defines a field extension as an
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is exactly the field. For example, the only finite field extension of the real numbers is the complex numbers, while the quaternions are a central simple algebra over the reals, and all CSAs over the reals are
4287: 4028:). On the opposite, even when one knows a transcendence basis, it may be difficult to decide whether the extension is purely separable, and if it is so, it may be difficult to find a transcendence basis 3539: 2194: 1861: 4560: 4478: 4095: 2767: 1635: 1845: 1164: 3291: 2156: 1593: 1487: 1045: 1100: 4962: 5323: 2961: 2496: 1680: 4210: 4140: 3634: 2653: 2181: 1805: 4422: 3777: 3751: 3729: 3707: 3685: 3561: 2983: 2456: 1455: 1433: 1411: 1386: 245: 88: 3609: 3585: 3111: 4692: 3144: 862: 4656: 2575: 1695: 1561: 4623: 3642:
it is finite. This implies that an extension is algebraic if and only if it is the union of its finite subextensions, and that every finite extension is algebraic.
4586: 4504: 4400: 5040: 4920: 4858: 4827: 4763: 3959: 3919: 3819: 3486: 3071: 893: 788: 760: 732: 704: 676: 567: 536: 469: 59: 4374: 1529: 4712: 4351: 4327: 4307: 4160: 4115: 398: 360: 340: 313: 285: 265: 216: 193: 622: 2779: 5054:). The significance of Galois extensions and Galois groups is that they allow a complete description of the intermediate fields: there is a 4588:
is a transcendence basis that does not generates the whole extension. However the extension is purely transcendental since, if one set
2466:. Another extension field of the rationals, which is also important in number theory, although not a finite extension, is the field of 3985:, but, however, there are extensions with this property which are not purely transcendental—a class of such extensions take the form 4215: 3211:
is a finite extension. In this case the degree of the extension equals the degree of the minimal polynomial, and a basis of the
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of a rational variety is equivalent with the problem of finding a transcendence basis that generates the whole extension.
5331: 4509: 4427: 5129:" on associated algebraic objects. For example, given a real vector space, one can produce a complex vector space via 3893:. All transcendence bases have the same cardinality, equal to the transcendence degree of the extension. An extension 5309: 4050: 3167: 2711: 1598: 1215: 1810: 1105: 3229: 2126: 1566: 1460: 992: 1358:
Henceforth, we will suppress the injective homomorphism and assume that we are dealing with actual subfields.
5402: 5348: 3496:. Equivalently, an algebraic extension is an extension that is generated by algebraic elements. For example, 373:, which is itself a subfield of the complex numbers. More generally, the field of rational numbers is (or is 1320:
or any other kind of division. Instead the slash expresses the word "over". In some literature the notation
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The degree of an extension is 1 if and only if the two fields are equal. In this case, the extension is a
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non-zero ring homomorphism between fields is injective because fields do not possess nontrivial proper
2932: 2472: 1639: 5419: 4888: 3830: 1256: 98: 4169: 5163: 4726: 4120: 3788: 3614: 2596: 2161: 1785: 1252: 582: 404: 378: 4405: 3760: 3734: 3712: 3690: 3668: 3544: 2966: 2439: 1438: 1416: 1394: 1369: 224: 67: 3590: 3566: 3092: 149: 5351:, vol. 211 (Corrected fourth printing, revised third ed.), New York: Springer-Verlag, 1772:{\displaystyle \mathbb {Q} ({\sqrt {2}})=\left\{a+b{\sqrt {2}}\mid a,b\in \mathbb {Q} \right\},} 5087: 4770: 3175: 2578: 2459: 292: 4661: 3116: 796: 4628: 2547: 1534: 288: 4591: 5142: 5126: 5120: 5095: 4873: 4565: 4483: 4379: 3846: 2922: 8: 5134: 5017: 4897: 4861: 4835: 4804: 4740: 3936: 3896: 3882: 3796: 3463: 3048: 3032: 2586: 1344: 870: 765: 737: 709: 681: 653: 544: 513: 446: 196: 62: 36: 4356: 3661:, and also the smallest extension field such that every polynomial with coefficients in 1492: 5079: 4891:
states that every finite separable extension has a primitive element (i.e. is simple).
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of degree 2 and 4 respectively. It is also a simple extension, as one can show that
1336: 1285: 5130: 4881: 4766: 3159: 1207: 153: 2837:{\displaystyle \operatorname {GF} (p)=\mathbb {F} _{p}=\mathbb {Z} /p\mathbb {Z} } 5370: 5168: 5104: 5075: 4163: 2915: 2675: 2514: 366: 18:
Construction of a larger algebraic field by "adding elements" to a smaller field
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is a transcendence basis of the extension, it doesn't necessarily follow that
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under the operations of addition, subtraction, multiplication, and taking the
5413: 5004: 2590: 2510: 2467: 2463: 1313: 157: 3845:. The largest cardinality of an algebraically independent set is called the 5000: 4965: 4717:
Purely transcendental extensions of an algebraically closed field occur as
3216: 2706: 2698: 578: 5133:. In addition to vector spaces, one can perform extension of scalars for 2774: 1389: 374: 370: 142: 22: 5340: 5138: 5108: 3082: 2884: 2690:
in which the given polynomial splits into a product of linear factors.
5055: 4999:. When the extension is Galois this automorphism group is called the 407:
of a subfield is the same as the characteristic of the larger field.
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to the reals or the quaternions. CSAs can be further generalized to
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that is a field with respect to the field operations inherited from
5094:(no non-trivial 2-sided ideals, just as for a field) and where the 5059: 1348: 130: 1259:, which does not hold true for fields of non-zero characteristic. 5083: 26: 5378: 3113:
is algebraic over the rational numbers, because it is a root of
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is a transcendence basis that does not generates the extension
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in turn is an extension field of the field of rational numbers
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It is common to construct an extension field of a given field
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is a positive integer, there is a unique (up to isomorphism)
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0, every finite extension is a simple extension. This is the
4282:{\displaystyle \mathbb {Q} (X)/\langle Y^{2}-X^{3}\rangle ,} 2907:. This field of rational functions is an extension field of 4876:, i.e., has no repeated roots in an algebraic closure over 3973:). Such an extension has the property that all elements of 3837:
if no non-trivial polynomial relation with coefficients in
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if we identify every complex number with the corresponding
4732: 145:; the real numbers are a subfield of the complex numbers. 2674:
By iterating the above construction, one can construct a
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also clearly a simple extension. The degree is 2 because
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is a field extension that is both normal and separable.
3320:. This results from the preceding characterization: if 1312:
is purely formal and does not imply the formation of a
5042:, one is often interested in the intermediate fields 5020: 4931: 4900: 4838: 4807: 4743: 4700: 4664: 4631: 4594: 4568: 4512: 4486: 4430: 4408: 4382: 4359: 4339: 4315: 4295: 4218: 4172: 4148: 4123: 4103: 4053: 3939: 3899: 3799: 3763: 3737: 3715: 3693: 3671: 3617: 3593: 3569: 3547: 3534:{\displaystyle \mathbb {Q} ({\sqrt {2}},{\sqrt {3}})} 3502: 3466: 3232: 3119: 3095: 3051: 2969: 2935: 2782: 2714: 2599: 2550: 2475: 2442: 2192: 2164: 2129: 1859: 1813: 1788: 1698: 1642: 1601: 1569: 1537: 1495: 1463: 1441: 1419: 1397: 1372: 1108: 1053: 995: 873: 799: 768: 740: 712: 684: 656: 598: 547: 516: 449: 386: 348: 328: 301: 273: 267:. Equivalently, a subfield is a subset that contains 253: 227: 204: 181: 70: 39: 5107:, where the base field is replaced by a commutative 5003:of the extension. Extensions whose Galois group is 4829:is normal and which is minimal with this property. 3015:), consisting of the rational functions defined on 5034: 4956: 4914: 4852: 4821: 4757: 4706: 4686: 4650: 4617: 4580: 4554: 4498: 4472: 4416: 4394: 4368: 4345: 4321: 4301: 4281: 4204: 4154: 4134: 4109: 4089: 3953: 3929:if and only if there exists a transcendence basis 3913: 3813: 3771: 3745: 3723: 3701: 3679: 3628: 3603: 3579: 3555: 3533: 3480: 3285: 3138: 3105: 3065: 2977: 2955: 2836: 2761: 2663:contain an element whose square is −1 (namely the 2647: 2569: 2490: 2450: 2425: 2175: 2150: 2112: 1839: 1799: 1771: 1674: 1629: 1587: 1555: 1523: 1481: 1449: 1427: 1405: 1380: 1158: 1094: 1039: 887: 856: 782: 754: 726: 698: 670: 616: 561: 530: 463: 392: 354: 334: 307: 279: 259: 239: 210: 187: 82: 53: 5090:(CSAs) – ring extensions over a field, which are 4555:{\displaystyle \mathbb {Q} (x,y)/\mathbb {Q} (x)} 4473:{\displaystyle \mathbb {Q} (x,y)/\mathbb {Q} (x)} 5411: 5367:Introduction To Modern Algebra, Revised Edition 5137:defined over the field, such as polynomials or 4090:{\displaystyle \mathbb {Q} (x,y)/\mathbb {Q} ,} 4864:if the minimal polynomial of every element of 3653:an isomorphism the largest extension field of 3383:is also finite, as well as the sub extensions 2762:{\displaystyle GF(p^{n})=\mathbb {F} _{p^{n}}} 1595:is finite. This is a simple extension because 1630:{\displaystyle \mathbb {C} =\mathbb {R} (i).} 915:. It is the intersection of all subfields of 4781:completely factors into linear factors over 4575: 4569: 4493: 4487: 4389: 4383: 4273: 4247: 2773:elements; this is an extension field of the 1840:{\displaystyle \left\{1,{\sqrt {2}}\right\}} 1550: 1538: 1147: 1115: 1034: 1002: 3782: 3488:is an extension such that every element of 1159:{\displaystyle K(\{x_{1},\ldots ,x_{n}\}),} 3286:{\displaystyle 1,s,s^{2},\ldots ,s^{d-1},} 2963:It is a transcendental extension field of 647:is an extension that has a finite degree. 635:. Extensions of degree 2 and 3 are called 129:. For example, under the usual notions of 4539: 4514: 4457: 4432: 4410: 4220: 4125: 4080: 4055: 3765: 3739: 3717: 3695: 3673: 3619: 3549: 3504: 3308:form a subextension, which is called the 3297:is the degree of the minimal polynomial. 2971: 2937: 2830: 2817: 2803: 2742: 2478: 2444: 2407: 2233: 2198: 2166: 2151:{\displaystyle \mathbb {Q} ({\sqrt {2}})} 2131: 2094: 1985: 1904: 1865: 1790: 1757: 1700: 1655: 1647: 1611: 1603: 1588:{\displaystyle \mathbb {C} /\mathbb {R} } 1581: 1571: 1508: 1500: 1482:{\displaystyle \mathbb {C} /\mathbb {Q} } 1475: 1465: 1443: 1421: 1399: 1374: 1040:{\displaystyle S=\{x_{1},\ldots ,x_{n}\}} 5317: 5295: 5280: 5268: 5256: 5244: 5232: 5208: 5196: 5058:between the intermediate fields and the 1347:, so field extensions are precisely the 5114: 5074:Field extensions can be generalized to 4733:Normal, separable and Galois extensions 5412: 5086:. A closer non-commutative analog are 5062:of the Galois group, described by the 3857:. It is always possible to find a set 3026: 1388:is an extension field of the field of 1095:{\displaystyle K(x_{1},\ldots ,x_{n})} 5364: 5220: 5339: 5064:fundamental theorem of Galois theory 4212:Such an extension can be defined as 4047:For example, consider the extension 3197:if and only if the simple extension 443:. Such a field extension is denoted 148:Field extensions are fundamental in 3649:has an algebraic closure, which is 1667: 1489:is also a field extension. We have 585:of this vector space is called the 490:, which is in turn an extension of 13: 5298:A First Course In Abstract Algebra 5147:extension of scalars: applications 5125:Given a field extension, one can " 5069: 3709:, but not an algebraic closure of 1686:), so this extension is infinite. 903:, there is a smallest subfield of 790:are finite. In this case, one has 410: 14: 5431: 5385: 4957:{\displaystyle {\text{Aut}}(L/K)} 4797:, which is an extension field of 3861:, algebraically independent over 1232:is often said to result from the 4714:generates the whole extension. 3638:A simple extension is algebraic 2956:{\displaystyle \mathbb {C} (M).} 2589:generated by this polynomial is 2491:{\displaystyle \mathbb {Q} _{p}} 1675:{\displaystyle ={\mathfrak {c}}} 1284:) is isomorphic to the field of 322:, the latter definition implies 3665:has a root in it. For example, 1221:An extension field of the form 439:, and this pair of fields is a 377:to) a subfield of any field of 5274: 5262: 5250: 5238: 5226: 5214: 5202: 5190: 4951: 4937: 4549: 4543: 4530: 4518: 4467: 4461: 4448: 4436: 4239: 4233: 4230: 4224: 4205:{\displaystyle y^{2}-x^{3}=0.} 4071: 4059: 3731:, as it is not algebraic over 3528: 3508: 3328:are algebraic, the extensions 2947: 2941: 2911:. This extension is infinite. 2795: 2789: 2734: 2721: 2642: 2623: 2615: 2609: 2370: 2349: 2334: 2313: 2304: 2284: 2257: 2237: 2222: 2202: 2145: 2135: 2123:is an extension field of both 1714: 1704: 1659: 1643: 1621: 1615: 1512: 1496: 1150: 1112: 1089: 1057: 848: 836: 830: 818: 812: 800: 734:is finite if and only if both 611: 599: 141:are an extension field of the 90:, such that the operations of 1: 5349:Graduate Texts in Mathematics 5289: 4376:Obviously, the singleton set 4135:{\displaystyle \mathbb {Q} ,} 4012:is purely transcendental and 3841:exists among the elements of 3629:{\displaystyle \mathbb {Q} .} 3541:is an algebraic extension of 3174:. This minimal polynomial is 2682:. This is an extension field 2648:{\displaystyle L=K/(X^{2}+1)} 2536:does not contain any element 2532:). Suppose for instance that 2176:{\displaystyle \mathbb {Q} ,} 1800:{\displaystyle \mathbb {Q} ,} 1563:is a basis, so the extension 1366:The field of complex numbers 1188:consists of a single element 5324:Blaisdell Publishing Company 5014:For a given field extension 4785:. Every algebraic extension 4417:{\displaystyle \mathbb {Q} } 3772:{\displaystyle \mathbb {Q} } 3746:{\displaystyle \mathbb {Q} } 3724:{\displaystyle \mathbb {Q} } 3702:{\displaystyle \mathbb {R} } 3680:{\displaystyle \mathbb {C} } 3556:{\displaystyle \mathbb {Q} } 2978:{\displaystyle \mathbb {C} } 2855:, we can consider the field 2451:{\displaystyle \mathbb {Q} } 1684:cardinality of the continuum 1450:{\displaystyle \mathbb {Q} } 1428:{\displaystyle \mathbb {R} } 1406:{\displaystyle \mathbb {R} } 1381:{\displaystyle \mathbb {C} } 362:have the same zero element. 240:{\displaystyle K\subseteq L} 83:{\displaystyle K\subseteq L} 7: 5398:Encyclopedia of Mathematics 5152: 4725:. The problem of finding a 4001:are algebraically closed. 3877:) is algebraic. Such a set 3687:is an algebraic closure of 3604:{\displaystyle {\sqrt {3}}} 3580:{\displaystyle {\sqrt {2}}} 3300:The set of the elements of 3106:{\displaystyle {\sqrt {2}}} 3019:, is an extension field of 2993:. More generally, given an 1361: 167: 10: 5436: 5296:Fraleigh, John B. (1976), 5118: 4964:, consisting of all field 4894:Given any field extension 3786: 3162:of lowest degree that has 3030: 2544:= −1. Then the polynomial 1299: 365:For example, the field of 5300:(2nd ed.), Reading: 4889:primitive element theorem 3831:algebraically independent 2655:is an extension field of 1782:is an extension field of 1276:is not finite, the field 1257:primitive element theorem 160:, and are widely used in 5318:Herstein, I. N. (1964), 5184: 5164:Glossary of field theory 4793:admits a normal closure 4727:rational parametrization 4687:{\displaystyle y=t^{3},} 3981:are transcendental over 3793:Given a field extension 3789:Transcendental extension 3783:Transcendental extension 3657:which is algebraic over 3304:that are algebraic over 3166:as a root is called the 3139:{\displaystyle x^{2}-2.} 867:Given a field extension 857:{\displaystyle =\cdot .} 541:Given a field extension 295:of a nonzero element of 5365:McCoy, Neal H. (1968), 5088:central simple algebras 4832:An algebraic extension 4737:An algebraic extension 4651:{\displaystyle x=t^{2}} 4402:is transcendental over 4117:is transcendental over 2929:is a field, denoted by 2903:of the polynomial ring 2883:) are fractions of two 2678:of any polynomial from 2570:{\displaystyle X^{2}+1} 2524:for a given polynomial 2520:in order to "create" a 2460:algebraic number fields 1847:can serve as a basis. 1556:{\displaystyle \{1,i\}} 150:algebraic number theory 5393:"Extension of a field" 5036: 4958: 4922:, we can consider its 4916: 4854: 4823: 4771:irreducible polynomial 4759: 4708: 4688: 4652: 4619: 4618:{\displaystyle t=y/x,} 4582: 4556: 4500: 4474: 4418: 4396: 4370: 4347: 4323: 4303: 4283: 4206: 4156: 4136: 4111: 4091: 3955: 3915: 3815: 3773: 3757:is not algebraic over 3747: 3725: 3703: 3681: 3630: 3605: 3581: 3557: 3535: 3482: 3287: 3140: 3107: 3067: 2979: 2957: 2838: 2763: 2649: 2571: 2492: 2452: 2427: 2177: 2152: 2114: 1841: 1801: 1773: 1676: 1631: 1589: 1557: 1525: 1483: 1451: 1429: 1407: 1382: 1262:If a simple extension 1160: 1096: 1047:is finite, one writes 1041: 889: 858: 784: 756: 728: 700: 672: 618: 563: 532: 504:intermediate extension 465: 394: 356: 336: 309: 281: 261: 241: 212: 189: 152:, and in the study of 84: 55: 5143:group representations 5037: 4959: 4917: 4887:A consequence of the 4855: 4824: 4760: 4709: 4689: 4653: 4620: 4583: 4581:{\displaystyle \{y\}} 4557: 4501: 4499:{\displaystyle \{x\}} 4475: 4419: 4397: 4395:{\displaystyle \{x\}} 4371: 4348: 4324: 4304: 4284: 4207: 4157: 4137: 4112: 4092: 3956: 3925:purely transcendental 3916: 3816: 3774: 3748: 3726: 3704: 3682: 3631: 3606: 3582: 3558: 3536: 3483: 3288: 3141: 3108: 3085:with coefficients in 3068: 3045:of a field extension 2980: 2958: 2923:meromorphic functions 2871:with coefficients in 2839: 2764: 2650: 2572: 2493: 2462:and are important in 2453: 2436:Finite extensions of 2428: 2178: 2153: 2115: 1842: 1802: 1774: 1677: 1632: 1590: 1558: 1526: 1484: 1452: 1430: 1408: 1383: 1161: 1097: 1042: 890: 859: 785: 757: 729: 701: 673: 650:Given two extensions 619: 564: 533: 466: 395: 369:is a subfield of the 357: 337: 310: 282: 262: 242: 213: 190: 85: 56: 5135:associative algebras 5121:Extension of scalars 5115:Extension of scalars 5018: 4929: 4898: 4836: 4805: 4741: 4698: 4662: 4629: 4592: 4566: 4510: 4484: 4480:is algebraic; hence 4428: 4406: 4380: 4357: 4337: 4313: 4293: 4216: 4170: 4146: 4121: 4101: 4051: 3937: 3897: 3847:transcendence degree 3797: 3761: 3735: 3713: 3691: 3669: 3615: 3591: 3567: 3545: 3500: 3464: 3230: 3117: 3093: 3049: 2967: 2933: 2780: 2712: 2597: 2548: 2473: 2440: 2190: 2162: 2127: 1857: 1811: 1786: 1696: 1640: 1599: 1567: 1535: 1493: 1461: 1439: 1417: 1395: 1370: 1339:between two fields. 1106: 1051: 993: 927:, and is denoted by 871: 797: 766: 738: 710: 682: 654: 637:quadratic extensions 596: 545: 514: 447: 384: 346: 326: 299: 271: 251: 225: 202: 179: 68: 37: 5141:and the associated 5078:which consist of a 5035:{\displaystyle L/K} 4915:{\displaystyle L/K} 4853:{\displaystyle L/K} 4822:{\displaystyle L/K} 4777:that has a root in 4758:{\displaystyle L/K} 4331:equivalence classes 3954:{\displaystyle L/K} 3914:{\displaystyle L/K} 3883:transcendence basis 3814:{\displaystyle L/K} 3611:are algebraic over 3481:{\displaystyle L/K} 3459:algebraic extension 3454:are all algebraic. 3436:). It follows that 3066:{\displaystyle L/K} 3033:Algebraic extension 3027:Algebraic extension 2585:, consequently the 2498:for a prime number 888:{\displaystyle L/K} 783:{\displaystyle M/L} 755:{\displaystyle L/K} 727:{\displaystyle M/K} 699:{\displaystyle M/L} 671:{\displaystyle L/K} 569:, the larger field 562:{\displaystyle L/K} 531:{\displaystyle L/K} 486:is an extension of 464:{\displaystyle L/K} 54:{\displaystyle L/K} 5096:center of the ring 5032: 5009:abelian extensions 4954: 4924:automorphism group 4912: 4850: 4819: 4755: 4723:rational varieties 4704: 4684: 4648: 4615: 4578: 4552: 4496: 4470: 4424:and the extension 4414: 4392: 4369:{\displaystyle Y.} 4366: 4343: 4319: 4299: 4279: 4202: 4152: 4132: 4107: 4087: 3951: 3911: 3811: 3769: 3743: 3721: 3699: 3677: 3626: 3601: 3577: 3553: 3531: 3492:is algebraic over 3478: 3283: 3193:is algebraic over 3168:minimal polynomial 3154:is algebraic over 3136: 3103: 3073:is algebraic over 3063: 2975: 2953: 2901:field of fractions 2875:; the elements of 2865:rational functions 2834: 2759: 2645: 2567: 2488: 2448: 2423: 2421: 2173: 2148: 2110: 2108: 1837: 1797: 1769: 1672: 1627: 1585: 1553: 1524:{\displaystyle =2} 1521: 1479: 1447: 1425: 1403: 1378: 1353:category of fields 1286:rational fractions 1218:of the extension. 1177:finitely generated 1166:and one says that 1156: 1092: 1037: 949:"). One says that 885: 854: 780: 752: 724: 696: 668: 643:, respectively. A 614: 592:and is denoted by 559: 528: 500:intermediate field 461: 390: 352: 332: 305: 277: 257: 237: 208: 185: 162:algebraic geometry 80: 51: 25:, particularly in 5358:978-0-387-95385-4 5320:Topics In Algebra 5179:Regular extension 5174:Primary extension 5101:Brauer equivalent 4935: 4707:{\displaystyle t} 4346:{\displaystyle X} 4322:{\displaystyle y} 4302:{\displaystyle x} 4155:{\displaystyle y} 4110:{\displaystyle x} 3599: 3575: 3526: 3516: 3365:are finite. Thus 3310:algebraic closure 3101: 3037:Algebraic element 2995:algebraic variety 2987:constant function 2921:, the set of all 2367: 2357: 2331: 2321: 2302: 2292: 2255: 2245: 2220: 2210: 2143: 2064: 2051: 2038: 1998: 1967: 1932: 1917: 1889: 1879: 1830: 1739: 1712: 1337:ring homomorphism 1216:primitive element 631:trivial extension 498:is said to be an 419:is a subfield of 393:{\displaystyle 0} 355:{\displaystyle L} 335:{\displaystyle K} 308:{\displaystyle K} 280:{\displaystyle 1} 260:{\displaystyle L} 211:{\displaystyle L} 188:{\displaystyle K} 5427: 5420:Field extensions 5406: 5381: 5361: 5336: 5314: 5284: 5278: 5272: 5266: 5260: 5254: 5248: 5242: 5236: 5230: 5224: 5218: 5212: 5206: 5200: 5194: 5131:complexification 5105:Azumaya algebras 5041: 5039: 5038: 5033: 5028: 4963: 4961: 4960: 4955: 4947: 4936: 4933: 4921: 4919: 4918: 4913: 4908: 4882:Galois extension 4859: 4857: 4856: 4851: 4846: 4828: 4826: 4825: 4820: 4815: 4764: 4762: 4761: 4756: 4751: 4713: 4711: 4710: 4705: 4693: 4691: 4690: 4685: 4680: 4679: 4657: 4655: 4654: 4649: 4647: 4646: 4624: 4622: 4621: 4616: 4608: 4587: 4585: 4584: 4579: 4561: 4559: 4558: 4553: 4542: 4537: 4517: 4505: 4503: 4502: 4497: 4479: 4477: 4476: 4471: 4460: 4455: 4435: 4423: 4421: 4420: 4415: 4413: 4401: 4399: 4398: 4393: 4375: 4373: 4372: 4367: 4352: 4350: 4349: 4344: 4328: 4326: 4325: 4320: 4308: 4306: 4305: 4300: 4288: 4286: 4285: 4280: 4272: 4271: 4259: 4258: 4246: 4223: 4211: 4209: 4208: 4203: 4195: 4194: 4182: 4181: 4166:of the equation 4161: 4159: 4158: 4153: 4141: 4139: 4138: 4133: 4128: 4116: 4114: 4113: 4108: 4096: 4094: 4093: 4088: 4083: 4078: 4058: 3977:except those of 3960: 3958: 3957: 3952: 3947: 3927: 3926: 3920: 3918: 3917: 3912: 3907: 3820: 3818: 3817: 3812: 3807: 3778: 3776: 3775: 3770: 3768: 3756: 3752: 3750: 3749: 3744: 3742: 3730: 3728: 3727: 3722: 3720: 3708: 3706: 3705: 3700: 3698: 3686: 3684: 3683: 3678: 3676: 3635: 3633: 3632: 3627: 3622: 3610: 3608: 3607: 3602: 3600: 3595: 3586: 3584: 3583: 3578: 3576: 3571: 3562: 3560: 3559: 3554: 3552: 3540: 3538: 3537: 3532: 3527: 3522: 3517: 3512: 3507: 3487: 3485: 3484: 3479: 3474: 3445: 3435: 3428: 3414: 3400: 3382: 3364: 3341: 3292: 3290: 3289: 3284: 3279: 3278: 3254: 3253: 3210: 3160:monic polynomial 3145: 3143: 3142: 3137: 3129: 3128: 3112: 3110: 3109: 3104: 3102: 3097: 3072: 3070: 3069: 3064: 3059: 3000:over some field 2984: 2982: 2981: 2976: 2974: 2962: 2960: 2959: 2954: 2940: 2867:in the variable 2843: 2841: 2840: 2835: 2833: 2825: 2820: 2812: 2811: 2806: 2768: 2766: 2765: 2760: 2758: 2757: 2756: 2755: 2745: 2733: 2732: 2654: 2652: 2651: 2646: 2635: 2634: 2622: 2576: 2574: 2573: 2568: 2560: 2559: 2497: 2495: 2494: 2489: 2487: 2486: 2481: 2458:are also called 2457: 2455: 2454: 2449: 2447: 2432: 2430: 2429: 2424: 2422: 2415: 2411: 2410: 2378: 2377: 2368: 2363: 2358: 2353: 2342: 2341: 2332: 2327: 2322: 2317: 2303: 2298: 2293: 2288: 2263: 2256: 2251: 2246: 2241: 2236: 2221: 2216: 2211: 2206: 2201: 2182: 2180: 2179: 2174: 2169: 2157: 2155: 2154: 2149: 2144: 2139: 2134: 2119: 2117: 2116: 2111: 2109: 2102: 2098: 2097: 2065: 2060: 2052: 2047: 2039: 2034: 2012: 2008: 2004: 2003: 1999: 1994: 1988: 1968: 1963: 1941: 1937: 1933: 1928: 1922: 1918: 1913: 1907: 1895: 1891: 1890: 1885: 1880: 1875: 1868: 1846: 1844: 1843: 1838: 1836: 1832: 1831: 1826: 1806: 1804: 1803: 1798: 1793: 1778: 1776: 1775: 1770: 1765: 1761: 1760: 1740: 1735: 1713: 1708: 1703: 1681: 1679: 1678: 1673: 1671: 1670: 1658: 1650: 1636: 1634: 1633: 1628: 1614: 1606: 1594: 1592: 1591: 1586: 1584: 1579: 1574: 1562: 1560: 1559: 1554: 1530: 1528: 1527: 1522: 1511: 1503: 1488: 1486: 1485: 1480: 1478: 1473: 1468: 1457:. Clearly then, 1456: 1454: 1453: 1448: 1446: 1434: 1432: 1431: 1426: 1424: 1412: 1410: 1409: 1404: 1402: 1387: 1385: 1384: 1379: 1377: 1275: 1238: 1237: 1231: 1208:simple extension 1205: 1192:, the extension 1179: 1178: 1165: 1163: 1162: 1157: 1146: 1145: 1127: 1126: 1101: 1099: 1098: 1093: 1088: 1087: 1069: 1068: 1046: 1044: 1043: 1038: 1033: 1032: 1014: 1013: 944: 943: 894: 892: 891: 886: 881: 863: 861: 860: 855: 789: 787: 786: 781: 776: 761: 759: 758: 753: 748: 733: 731: 730: 725: 720: 706:, the extension 705: 703: 702: 697: 692: 677: 675: 674: 669: 664: 645:finite extension 641:cubic extensions 633: 632: 623: 621: 620: 617:{\displaystyle } 615: 590:of the extension 568: 566: 565: 560: 555: 537: 535: 534: 529: 524: 470: 468: 467: 462: 457: 399: 397: 396: 391: 367:rational numbers 361: 359: 358: 353: 341: 339: 338: 333: 321: 314: 312: 311: 306: 286: 284: 283: 278: 266: 264: 263: 258: 246: 244: 243: 238: 217: 215: 214: 209: 194: 192: 191: 186: 154:polynomial roots 105:. In this case, 89: 87: 86: 81: 60: 58: 57: 52: 47: 5435: 5434: 5430: 5429: 5428: 5426: 5425: 5424: 5410: 5409: 5391: 5388: 5371:Allyn and Bacon 5359: 5334: 5312: 5292: 5287: 5279: 5275: 5267: 5263: 5255: 5251: 5243: 5239: 5231: 5227: 5219: 5215: 5207: 5203: 5195: 5191: 5187: 5169:Tower of fields 5155: 5123: 5117: 5082:and one of its 5076:ring extensions 5072: 5070:Generalizations 5024: 5019: 5016: 5015: 4943: 4932: 4930: 4927: 4926: 4904: 4899: 4896: 4895: 4842: 4837: 4834: 4833: 4811: 4806: 4803: 4802: 4747: 4742: 4739: 4738: 4735: 4719:function fields 4699: 4696: 4695: 4675: 4671: 4663: 4660: 4659: 4642: 4638: 4630: 4627: 4626: 4604: 4593: 4590: 4589: 4567: 4564: 4563: 4538: 4533: 4513: 4511: 4508: 4507: 4485: 4482: 4481: 4456: 4451: 4431: 4429: 4426: 4425: 4409: 4407: 4404: 4403: 4381: 4378: 4377: 4358: 4355: 4354: 4338: 4335: 4334: 4314: 4311: 4310: 4294: 4291: 4290: 4267: 4263: 4254: 4250: 4242: 4219: 4217: 4214: 4213: 4190: 4186: 4177: 4173: 4171: 4168: 4167: 4147: 4144: 4143: 4124: 4122: 4119: 4118: 4102: 4099: 4098: 4079: 4074: 4054: 4052: 4049: 4048: 3943: 3938: 3935: 3934: 3924: 3923: 3903: 3898: 3895: 3894: 3803: 3798: 3795: 3794: 3791: 3785: 3764: 3762: 3759: 3758: 3754: 3738: 3736: 3733: 3732: 3716: 3714: 3711: 3710: 3694: 3692: 3689: 3688: 3672: 3670: 3667: 3666: 3618: 3616: 3613: 3612: 3594: 3592: 3589: 3588: 3570: 3568: 3565: 3564: 3548: 3546: 3543: 3542: 3521: 3511: 3503: 3501: 3498: 3497: 3470: 3465: 3462: 3461: 3437: 3430: 3416: 3402: 3384: 3366: 3343: 3329: 3268: 3264: 3249: 3245: 3231: 3228: 3227: 3198: 3124: 3120: 3118: 3115: 3114: 3096: 3094: 3091: 3090: 3089:. For example, 3055: 3050: 3047: 3046: 3039: 3031:Main articles: 3029: 2970: 2968: 2965: 2964: 2936: 2934: 2931: 2930: 2916:Riemann surface 2829: 2821: 2816: 2807: 2802: 2801: 2781: 2778: 2777: 2751: 2747: 2746: 2741: 2740: 2728: 2724: 2713: 2710: 2709: 2676:splitting field 2630: 2626: 2618: 2598: 2595: 2594: 2555: 2551: 2549: 2546: 2545: 2515:polynomial ring 2482: 2477: 2476: 2474: 2471: 2470: 2443: 2441: 2438: 2437: 2420: 2419: 2406: 2373: 2369: 2362: 2352: 2337: 2333: 2326: 2316: 2297: 2287: 2274: 2270: 2261: 2260: 2250: 2240: 2232: 2225: 2215: 2205: 2197: 2193: 2191: 2188: 2187: 2165: 2163: 2160: 2159: 2138: 2130: 2128: 2125: 2124: 2107: 2106: 2093: 2059: 2046: 2033: 2023: 2019: 2010: 2009: 1993: 1989: 1984: 1962: 1952: 1948: 1939: 1938: 1927: 1923: 1912: 1908: 1903: 1896: 1884: 1874: 1873: 1869: 1864: 1860: 1858: 1855: 1854: 1825: 1818: 1814: 1812: 1809: 1808: 1789: 1787: 1784: 1783: 1756: 1734: 1724: 1720: 1707: 1699: 1697: 1694: 1693: 1666: 1665: 1654: 1646: 1641: 1638: 1637: 1610: 1602: 1600: 1597: 1596: 1580: 1575: 1570: 1568: 1565: 1564: 1536: 1533: 1532: 1507: 1499: 1494: 1491: 1490: 1474: 1469: 1464: 1462: 1459: 1458: 1442: 1440: 1437: 1436: 1420: 1418: 1415: 1414: 1398: 1396: 1393: 1392: 1373: 1371: 1368: 1367: 1364: 1302: 1263: 1235: 1234: 1222: 1193: 1176: 1175: 1141: 1137: 1122: 1118: 1107: 1104: 1103: 1083: 1079: 1064: 1060: 1052: 1049: 1048: 1028: 1024: 1009: 1005: 994: 991: 990: 957:) is the field 941: 940: 877: 872: 869: 868: 798: 795: 794: 772: 767: 764: 763: 744: 739: 736: 735: 716: 711: 708: 707: 688: 683: 680: 679: 660: 655: 652: 651: 630: 629: 597: 594: 593: 551: 546: 543: 542: 520: 515: 512: 511: 453: 448: 445: 444: 441:field extension 429:extension field 413: 411:Extension field 385: 382: 381: 347: 344: 343: 327: 324: 323: 319: 300: 297: 296: 272: 269: 268: 252: 249: 248: 226: 223: 222: 203: 200: 199: 180: 177: 176: 170: 139:complex numbers 111:extension field 69: 66: 65: 61:) is a pair of 43: 38: 35: 34: 31:field extension 19: 12: 11: 5: 5433: 5423: 5422: 5408: 5407: 5387: 5386:External links 5384: 5383: 5382: 5362: 5357: 5337: 5333:978-1114541016 5332: 5315: 5310: 5302:Addison-Wesley 5291: 5288: 5286: 5285: 5283:, p. 169) 5281:Herstein (1964 5273: 5271:, p. 319) 5269:Fraleigh (1976 5261: 5259:, p. 363) 5257:Fraleigh (1976 5249: 5247:, p. 193) 5245:Herstein (1964 5237: 5235:, p. 298) 5233:Fraleigh (1976 5225: 5223:, p. 116) 5213: 5211:, p. 167) 5209:Herstein (1964 5201: 5199:, p. 293) 5197:Fraleigh (1976 5188: 5186: 5183: 5182: 5181: 5176: 5171: 5166: 5161: 5154: 5151: 5139:group algebras 5127:extend scalars 5119:Main article: 5116: 5113: 5092:simple algebra 5071: 5068: 5046:(subfields of 5031: 5027: 5023: 4953: 4950: 4946: 4942: 4939: 4911: 4907: 4903: 4849: 4845: 4841: 4818: 4814: 4810: 4754: 4750: 4746: 4734: 4731: 4703: 4683: 4678: 4674: 4670: 4667: 4645: 4641: 4637: 4634: 4614: 4611: 4607: 4603: 4600: 4597: 4577: 4574: 4571: 4551: 4548: 4545: 4541: 4536: 4532: 4529: 4526: 4523: 4520: 4516: 4495: 4492: 4489: 4469: 4466: 4463: 4459: 4454: 4450: 4447: 4444: 4441: 4438: 4434: 4412: 4391: 4388: 4385: 4365: 4362: 4342: 4318: 4298: 4278: 4275: 4270: 4266: 4262: 4257: 4253: 4249: 4245: 4241: 4238: 4235: 4232: 4229: 4226: 4222: 4201: 4198: 4193: 4189: 4185: 4180: 4176: 4151: 4131: 4127: 4106: 4086: 4082: 4077: 4073: 4070: 4067: 4064: 4061: 4057: 3950: 3946: 3942: 3921:is said to be 3910: 3906: 3902: 3810: 3806: 3802: 3787:Main article: 3784: 3781: 3767: 3741: 3719: 3697: 3675: 3640:if and only if 3625: 3621: 3598: 3574: 3551: 3530: 3525: 3520: 3515: 3510: 3506: 3477: 3473: 3469: 3282: 3277: 3274: 3271: 3267: 3263: 3260: 3257: 3252: 3248: 3244: 3241: 3238: 3235: 3226:) consists of 3146:If an element 3135: 3132: 3127: 3123: 3100: 3062: 3058: 3054: 3028: 3025: 3006:function field 2973: 2952: 2949: 2946: 2943: 2939: 2851:Given a field 2832: 2828: 2824: 2819: 2815: 2810: 2805: 2800: 2797: 2794: 2791: 2788: 2785: 2754: 2750: 2744: 2739: 2736: 2731: 2727: 2723: 2720: 2717: 2644: 2641: 2638: 2633: 2629: 2625: 2621: 2617: 2614: 2611: 2608: 2605: 2602: 2566: 2563: 2558: 2554: 2485: 2480: 2468:p-adic numbers 2446: 2434: 2433: 2418: 2414: 2409: 2405: 2402: 2399: 2396: 2393: 2390: 2387: 2384: 2381: 2376: 2372: 2366: 2361: 2356: 2351: 2348: 2345: 2340: 2336: 2330: 2325: 2320: 2315: 2312: 2309: 2306: 2301: 2296: 2291: 2286: 2283: 2280: 2277: 2273: 2269: 2266: 2264: 2262: 2259: 2254: 2249: 2244: 2239: 2235: 2231: 2228: 2226: 2224: 2219: 2214: 2209: 2204: 2200: 2196: 2195: 2172: 2168: 2147: 2142: 2137: 2133: 2121: 2120: 2105: 2101: 2096: 2092: 2089: 2086: 2083: 2080: 2077: 2074: 2071: 2068: 2063: 2058: 2055: 2050: 2045: 2042: 2037: 2032: 2029: 2026: 2022: 2018: 2015: 2013: 2011: 2007: 2002: 1997: 1992: 1987: 1983: 1980: 1977: 1974: 1971: 1966: 1961: 1958: 1955: 1951: 1947: 1944: 1942: 1940: 1936: 1931: 1926: 1921: 1916: 1911: 1906: 1902: 1899: 1897: 1894: 1888: 1883: 1878: 1872: 1867: 1863: 1862: 1835: 1829: 1824: 1821: 1817: 1796: 1792: 1780: 1779: 1768: 1764: 1759: 1755: 1752: 1749: 1746: 1743: 1738: 1733: 1730: 1727: 1723: 1719: 1716: 1711: 1706: 1702: 1669: 1664: 1661: 1657: 1653: 1649: 1645: 1626: 1623: 1620: 1617: 1613: 1609: 1605: 1583: 1578: 1573: 1552: 1549: 1546: 1543: 1540: 1520: 1517: 1514: 1510: 1506: 1502: 1498: 1477: 1472: 1467: 1445: 1423: 1401: 1376: 1363: 1360: 1318:quotient group 1301: 1298: 1253:characteristic 1155: 1152: 1149: 1144: 1140: 1136: 1133: 1130: 1125: 1121: 1117: 1114: 1111: 1091: 1086: 1082: 1078: 1075: 1072: 1067: 1063: 1059: 1056: 1036: 1031: 1027: 1023: 1020: 1017: 1012: 1008: 1004: 1001: 998: 975:generating set 907:that contains 884: 880: 876: 865: 864: 853: 850: 847: 844: 841: 838: 835: 832: 829: 826: 823: 820: 817: 814: 811: 808: 805: 802: 779: 775: 771: 751: 747: 743: 723: 719: 715: 695: 691: 687: 667: 663: 659: 613: 610: 607: 604: 601: 558: 554: 550: 527: 523: 519: 460: 456: 452: 412: 409: 405:characteristic 389: 379:characteristic 351: 331: 304: 276: 256: 236: 233: 230: 207: 184: 169: 166: 135:multiplication 79: 76: 73: 50: 46: 42: 17: 9: 6: 4: 3: 2: 5432: 5421: 5418: 5417: 5415: 5404: 5400: 5399: 5394: 5390: 5389: 5380: 5376: 5372: 5368: 5363: 5360: 5354: 5350: 5346: 5342: 5338: 5335: 5329: 5325: 5321: 5316: 5313: 5311:0-201-01984-1 5307: 5303: 5299: 5294: 5293: 5282: 5277: 5270: 5265: 5258: 5253: 5246: 5241: 5234: 5229: 5222: 5217: 5210: 5205: 5198: 5193: 5189: 5180: 5177: 5175: 5172: 5170: 5167: 5165: 5162: 5160: 5157: 5156: 5150: 5148: 5144: 5140: 5136: 5132: 5128: 5122: 5112: 5110: 5106: 5102: 5097: 5093: 5089: 5085: 5081: 5077: 5067: 5065: 5061: 5057: 5053: 5050:that contain 5049: 5045: 5029: 5025: 5021: 5012: 5010: 5006: 5002: 4998: 4994: 4990: 4986: 4982: 4978: 4974: 4970: 4967: 4966:automorphisms 4948: 4944: 4940: 4925: 4909: 4905: 4901: 4892: 4890: 4885: 4883: 4879: 4875: 4871: 4867: 4863: 4847: 4843: 4839: 4830: 4816: 4812: 4808: 4800: 4796: 4792: 4788: 4784: 4780: 4776: 4772: 4768: 4752: 4748: 4744: 4730: 4728: 4724: 4720: 4715: 4701: 4681: 4676: 4672: 4668: 4665: 4643: 4639: 4635: 4632: 4612: 4609: 4605: 4601: 4598: 4595: 4572: 4562:. Similarly, 4546: 4534: 4527: 4524: 4521: 4490: 4464: 4452: 4445: 4442: 4439: 4386: 4363: 4360: 4340: 4332: 4316: 4296: 4276: 4268: 4264: 4260: 4255: 4251: 4243: 4236: 4227: 4199: 4196: 4191: 4187: 4183: 4178: 4174: 4165: 4149: 4129: 4104: 4084: 4075: 4068: 4065: 4062: 4045: 4043: 4039: 4035: 4031: 4027: 4023: 4019: 4015: 4011: 4007: 4002: 4000: 3996: 3992: 3988: 3984: 3980: 3976: 3972: 3968: 3964: 3948: 3944: 3940: 3932: 3928: 3908: 3904: 3900: 3892: 3888: 3884: 3880: 3876: 3872: 3868: 3864: 3860: 3856: 3852: 3848: 3844: 3840: 3836: 3832: 3828: 3824: 3808: 3804: 3800: 3790: 3780: 3753:(for example 3664: 3660: 3656: 3652: 3648: 3643: 3641: 3636: 3623: 3596: 3572: 3523: 3518: 3513: 3495: 3491: 3475: 3471: 3467: 3460: 3455: 3453: 3449: 3444: 3440: 3433: 3427: 3423: 3419: 3413: 3409: 3405: 3399: 3395: 3391: 3387: 3381: 3377: 3373: 3369: 3362: 3358: 3354: 3350: 3346: 3340: 3336: 3332: 3327: 3323: 3319: 3315: 3311: 3307: 3303: 3298: 3296: 3280: 3275: 3272: 3269: 3265: 3261: 3258: 3255: 3250: 3246: 3242: 3239: 3236: 3233: 3225: 3221: 3218: 3214: 3209: 3205: 3201: 3196: 3192: 3188: 3183: 3181: 3177: 3173: 3169: 3165: 3161: 3157: 3153: 3149: 3133: 3130: 3125: 3121: 3098: 3088: 3084: 3081:of a nonzero 3080: 3076: 3060: 3056: 3052: 3044: 3038: 3034: 3024: 3022: 3018: 3014: 3010: 3007: 3003: 2999: 2996: 2992: 2988: 2950: 2944: 2928: 2924: 2920: 2917: 2912: 2910: 2906: 2902: 2898: 2894: 2891:, and indeed 2890: 2886: 2882: 2878: 2874: 2870: 2866: 2862: 2858: 2854: 2849: 2847: 2826: 2822: 2813: 2808: 2798: 2792: 2786: 2783: 2776: 2772: 2752: 2748: 2737: 2729: 2725: 2718: 2715: 2708: 2704: 2700: 2696: 2691: 2689: 2685: 2681: 2677: 2672: 2670: 2666: 2665:residue class 2662: 2658: 2639: 2636: 2631: 2627: 2619: 2612: 2606: 2603: 2600: 2592: 2588: 2584: 2580: 2564: 2561: 2556: 2552: 2543: 2539: 2535: 2531: 2527: 2523: 2519: 2516: 2512: 2511:quotient ring 2508: 2503: 2501: 2483: 2469: 2465: 2464:number theory 2461: 2416: 2412: 2403: 2400: 2397: 2394: 2391: 2388: 2385: 2382: 2379: 2374: 2364: 2359: 2354: 2346: 2343: 2338: 2328: 2323: 2318: 2310: 2307: 2299: 2294: 2289: 2281: 2278: 2275: 2271: 2267: 2265: 2252: 2247: 2242: 2229: 2227: 2217: 2212: 2207: 2186: 2185: 2184: 2170: 2140: 2103: 2099: 2090: 2087: 2084: 2081: 2078: 2075: 2072: 2069: 2066: 2061: 2056: 2053: 2048: 2043: 2040: 2035: 2030: 2027: 2024: 2020: 2016: 2014: 2005: 2000: 1995: 1990: 1981: 1978: 1975: 1972: 1969: 1964: 1959: 1956: 1953: 1949: 1945: 1943: 1934: 1929: 1924: 1919: 1914: 1909: 1900: 1898: 1892: 1886: 1881: 1876: 1870: 1853: 1852: 1851: 1848: 1833: 1827: 1822: 1819: 1815: 1794: 1766: 1762: 1753: 1750: 1747: 1744: 1741: 1736: 1731: 1728: 1725: 1721: 1717: 1709: 1692: 1691: 1690: 1687: 1685: 1662: 1651: 1624: 1618: 1607: 1576: 1547: 1544: 1541: 1518: 1515: 1504: 1470: 1391: 1359: 1356: 1354: 1350: 1346: 1342: 1338: 1335: 1329: 1327: 1323: 1319: 1315: 1314:quotient ring 1311: 1307: 1304:The notation 1297: 1295: 1291: 1287: 1283: 1279: 1274: 1270: 1266: 1260: 1258: 1254: 1249: 1247: 1243: 1239: 1229: 1225: 1219: 1217: 1213: 1209: 1204: 1200: 1196: 1191: 1187: 1183: 1173: 1169: 1153: 1142: 1138: 1134: 1131: 1128: 1123: 1119: 1109: 1084: 1080: 1076: 1073: 1070: 1065: 1061: 1054: 1029: 1025: 1021: 1018: 1015: 1010: 1006: 999: 996: 988: 984: 980: 976: 972: 968: 964: 960: 956: 952: 948: 945: 938: 934: 930: 926: 922: 919:that contain 918: 914: 910: 906: 902: 898: 895:and a subset 882: 878: 874: 851: 845: 842: 839: 833: 827: 824: 821: 815: 809: 806: 803: 793: 792: 791: 777: 773: 769: 749: 745: 741: 721: 717: 713: 693: 689: 685: 665: 661: 657: 648: 646: 642: 638: 634: 625: 608: 605: 602: 591: 589: 584: 580: 576: 572: 556: 552: 548: 539: 525: 521: 517: 509: 505: 501: 497: 493: 489: 485: 480: 478: 474: 458: 454: 450: 442: 438: 434: 430: 426: 422: 418: 408: 406: 401: 387: 380: 376: 372: 368: 363: 349: 329: 316: 302: 294: 290: 274: 254: 234: 231: 228: 221: 205: 198: 182: 175: 165: 163: 159: 158:Galois theory 155: 151: 146: 144: 140: 136: 132: 128: 124: 120: 116: 112: 108: 104: 100: 97: 94:are those of 93: 77: 74: 71: 64: 48: 44: 40: 32: 28: 24: 16: 5396: 5366: 5344: 5319: 5297: 5276: 5264: 5252: 5240: 5228: 5216: 5204: 5192: 5159:Field theory 5124: 5073: 5051: 5047: 5043: 5013: 5001:Galois group 4996: 4992: 4988: 4984: 4980: 4976: 4972: 4968: 4923: 4893: 4886: 4877: 4869: 4865: 4831: 4798: 4794: 4790: 4786: 4782: 4778: 4774: 4736: 4716: 4046: 4041: 4037: 4033: 4029: 4025: 4021: 4017: 4013: 4009: 4005: 4003: 3998: 3994: 3990: 3986: 3982: 3978: 3974: 3970: 3966: 3962: 3930: 3922: 3890: 3886: 3881:is called a 3878: 3874: 3870: 3866: 3865:, such that 3862: 3858: 3854: 3850: 3842: 3838: 3834: 3826: 3822: 3792: 3662: 3658: 3654: 3646: 3645:Every field 3644: 3637: 3493: 3489: 3458: 3456: 3451: 3447: 3442: 3438: 3431: 3425: 3421: 3417: 3411: 3407: 3403: 3397: 3393: 3389: 3385: 3379: 3375: 3371: 3367: 3360: 3356: 3352: 3348: 3344: 3338: 3334: 3330: 3325: 3321: 3317: 3313: 3305: 3301: 3299: 3294: 3223: 3219: 3217:vector space 3212: 3207: 3203: 3199: 3194: 3190: 3186: 3184: 3179: 3171: 3163: 3155: 3151: 3147: 3086: 3074: 3042: 3040: 3020: 3016: 3012: 3008: 3001: 2997: 2990: 2926: 2918: 2913: 2908: 2904: 2896: 2892: 2888: 2880: 2876: 2872: 2868: 2860: 2856: 2852: 2850: 2845: 2770: 2707:finite field 2702: 2699:prime number 2694: 2692: 2687: 2683: 2679: 2673: 2668: 2660: 2656: 2582: 2541: 2537: 2533: 2529: 2525: 2517: 2506: 2504: 2499: 2435: 2122: 1849: 1781: 1688: 1390:real numbers 1365: 1357: 1340: 1330: 1325: 1321: 1309: 1305: 1303: 1293: 1289: 1281: 1277: 1272: 1268: 1264: 1261: 1250: 1245: 1241: 1233: 1227: 1223: 1220: 1214:is called a 1211: 1206:is called a 1202: 1198: 1194: 1189: 1185: 1181: 1171: 1167: 986: 982: 978: 970: 966: 962: 958: 954: 950: 946: 939: 936: 935:) (read as " 932: 928: 924: 920: 916: 912: 908: 904: 900: 896: 866: 649: 644: 640: 636: 628: 626: 587: 579:vector space 574: 570: 540: 508:subextension 507: 503: 499: 495: 491: 487: 483: 481: 476: 472: 440: 436: 432: 428: 424: 420: 416: 414: 402: 371:real numbers 364: 317: 173: 171: 147: 143:real numbers 126: 122: 118: 114: 110: 106: 102: 95: 91: 30: 20: 15: 5341:Lang, Serge 5322:, Waltham: 5221:McCoy (1968 5007:are called 3993:where both 3821:, a subset 3185:An element 3176:irreducible 3077:if it is a 3041:An element 2989:defined on 2925:defined on 2885:polynomials 2775:prime field 2579:irreducible 1689:The field 1102:instead of 969:, and that 23:mathematics 5369:, Boston: 5290:References 5109:local ring 4860:is called 4801:such that 4765:is called 4032:such that 3961:such that 3829:is called 3563:, because 3083:polynomial 2848:elements. 1850:The field 1236:adjunction 471:(read as " 431:or simply 375:isomorphic 99:restricted 5403:EMS Press 5060:subgroups 5056:bijection 4874:separable 4862:separable 4769:if every 4694:and thus 4289:in which 4274:⟩ 4261:− 4248:⟨ 4184:− 3273:− 3259:… 3131:− 2899:) is the 2863:) of all 2787:⁡ 2404:∈ 2380:∣ 2091:∈ 2067:∣ 1982:∈ 1970:∣ 1754:∈ 1742:∣ 1349:morphisms 1334:injective 1328:is used. 1132:… 1074:… 1019:… 959:generated 834:⋅ 583:dimension 433:extension 320:1 – 1 = 0 287:, and is 232:⊆ 75:⊆ 33:(denoted 5414:Category 5379:68015225 5343:(2004), 5153:See also 5084:subrings 4991:for all 4625:one has 4329:are the 2914:Given a 1531:because 1362:Examples 174:subfield 168:Subfield 156:through 131:addition 123:subfield 5405:, 2001 5345:Algebra 5005:abelian 2697:is any 2591:maximal 2513:of the 1351:in the 1300:Caveats 989:. When 985:) over 494:, then 423:, then 293:inverse 27:algebra 5377:  5355:  5330:  5308:  4767:normal 4097:where 3450:and 1/ 3293:where 3158:, the 3004:, the 2659:which 2593:, and 1413:, and 1345:ideals 942:adjoin 588:degree 581:. The 427:is an 289:closed 220:subset 137:, the 109:is an 63:fields 5185:Notes 4979:with 4868:over 4162:is a 3833:over 3651:up to 3178:over 2887:over 2844:with 2769:with 2587:ideal 2540:with 2509:as a 1682:(the 1341:Every 1292:over 1184:. If 1180:over 1174:) is 973:is a 965:over 573:is a 510:) of 475:over 218:is a 197:field 195:of a 121:is a 5375:LCCN 5353:ISBN 5328:ISBN 5306:ISBN 5080:ring 4987:) = 4880:. A 4658:and 4353:and 4309:and 4164:root 4142:and 3997:and 3587:and 3429:(if 3415:and 3342:and 3324:and 3079:root 3035:and 2701:and 2661:does 2522:root 2158:and 1271:) / 1210:and 1201:) / 923:and 911:and 762:and 678:and 639:and 502:(or 479:"). 403:The 342:and 133:and 117:and 29:, a 4995:in 4934:Aut 4872:is 4773:in 4721:of 4333:of 4044:). 4004:If 3933:of 3885:of 3849:of 3825:of 3779:). 3457:An 3434:≠ 0 3424:) / 3420:(1/ 3410:) / 3396:) / 3378:) / 3355:) / 3337:) / 3316:in 3312:of 3206:) / 3189:of 3170:of 3150:of 2693:If 2686:of 2671:). 2667:of 2581:in 2577:is 1316:or 1288:in 1251:In 1244:to 1240:of 977:of 961:by 899:of 624:. 506:or 482:If 435:of 415:If 318:As 125:of 113:of 101:to 21:In 5416:: 5401:, 5395:, 5373:, 5347:, 5326:, 5304:, 5149:. 5111:. 5066:. 5011:. 4975:→ 4971:: 4200:0. 4036:= 4020:= 3965:= 3448:st 3446:, 3441:± 3408:st 3401:, 3392:± 3374:, 3351:)( 3182:. 3134:2. 3023:. 2784:GF 2502:. 1355:. 1308:/ 1296:. 1248:. 538:. 400:. 315:. 172:A 164:. 5052:K 5048:L 5044:F 5030:K 5026:/ 5022:L 4997:K 4993:x 4989:x 4985:x 4983:( 4981:α 4977:L 4973:L 4969:α 4952:) 4949:K 4945:/ 4941:L 4938:( 4910:K 4906:/ 4902:L 4878:K 4870:K 4866:L 4848:K 4844:/ 4840:L 4817:K 4813:/ 4809:L 4799:F 4795:L 4791:K 4789:/ 4787:F 4783:L 4779:L 4775:K 4753:K 4749:/ 4745:L 4702:t 4682:, 4677:3 4673:t 4669:= 4666:y 4644:2 4640:t 4636:= 4633:x 4613:, 4610:x 4606:/ 4602:y 4599:= 4596:t 4576:} 4573:y 4570:{ 4550:) 4547:x 4544:( 4540:Q 4535:/ 4531:) 4528:y 4525:, 4522:x 4519:( 4515:Q 4494:} 4491:x 4488:{ 4468:) 4465:x 4462:( 4458:Q 4453:/ 4449:) 4446:y 4443:, 4440:x 4437:( 4433:Q 4411:Q 4390:} 4387:x 4384:{ 4364:. 4361:Y 4341:X 4317:y 4297:x 4277:, 4269:3 4265:X 4256:2 4252:Y 4244:/ 4240:] 4237:Y 4234:[ 4231:) 4228:X 4225:( 4221:Q 4197:= 4192:3 4188:x 4179:2 4175:y 4150:y 4130:, 4126:Q 4105:x 4085:, 4081:Q 4076:/ 4072:) 4069:y 4066:, 4063:x 4060:( 4056:Q 4042:S 4040:( 4038:K 4034:L 4030:S 4026:S 4024:( 4022:K 4018:L 4014:S 4010:K 4008:/ 4006:L 3999:K 3995:L 3991:K 3989:/ 3987:L 3983:K 3979:K 3975:L 3971:S 3969:( 3967:K 3963:L 3949:K 3945:/ 3941:L 3931:S 3909:K 3905:/ 3901:L 3891:K 3889:/ 3887:L 3879:S 3875:S 3873:( 3871:K 3869:/ 3867:L 3863:K 3859:S 3855:K 3853:/ 3851:L 3843:S 3839:K 3835:K 3827:L 3823:S 3809:K 3805:/ 3801:L 3766:Q 3755:π 3740:Q 3718:Q 3696:R 3674:C 3663:K 3659:K 3655:K 3647:K 3624:. 3620:Q 3597:3 3573:2 3550:Q 3529:) 3524:3 3519:, 3514:2 3509:( 3505:Q 3494:K 3490:L 3476:K 3472:/ 3468:L 3452:s 3443:t 3439:s 3432:s 3426:K 3422:s 3418:K 3412:K 3406:( 3404:K 3398:K 3394:t 3390:s 3388:( 3386:K 3380:K 3376:t 3372:s 3370:( 3368:K 3363:) 3361:s 3359:( 3357:K 3353:t 3349:s 3347:( 3345:K 3339:K 3335:s 3333:( 3331:K 3326:t 3322:s 3318:L 3314:K 3306:K 3302:L 3295:d 3281:, 3276:1 3270:d 3266:s 3262:, 3256:, 3251:2 3247:s 3243:, 3240:s 3237:, 3234:1 3224:s 3222:( 3220:K 3215:- 3213:K 3208:K 3204:s 3202:( 3200:K 3195:K 3191:L 3187:s 3180:K 3172:x 3164:x 3156:K 3152:L 3148:x 3126:2 3122:x 3099:2 3087:K 3075:K 3061:K 3057:/ 3053:L 3043:x 3021:K 3017:V 3013:V 3011:( 3009:K 3002:K 2998:V 2991:M 2972:C 2951:. 2948:) 2945:M 2942:( 2938:C 2927:M 2919:M 2909:K 2905:K 2897:X 2895:( 2893:K 2889:K 2881:X 2879:( 2877:K 2873:K 2869:X 2861:X 2859:( 2857:K 2853:K 2846:p 2831:Z 2827:p 2823:/ 2818:Z 2814:= 2809:p 2804:F 2799:= 2796:) 2793:p 2790:( 2771:p 2753:n 2749:p 2743:F 2738:= 2735:) 2730:n 2726:p 2722:( 2719:F 2716:G 2703:n 2695:p 2688:K 2684:L 2680:K 2669:X 2657:K 2643:) 2640:1 2637:+ 2632:2 2628:X 2624:( 2620:/ 2616:] 2613:X 2610:[ 2607:K 2604:= 2601:L 2583:K 2565:1 2562:+ 2557:2 2553:X 2542:x 2538:x 2534:K 2530:X 2528:( 2526:f 2518:K 2507:K 2500:p 2484:p 2479:Q 2445:Q 2417:. 2413:} 2408:Q 2401:d 2398:, 2395:c 2392:, 2389:b 2386:, 2383:a 2375:3 2371:) 2365:3 2360:+ 2355:2 2350:( 2347:d 2344:+ 2339:2 2335:) 2329:3 2324:+ 2319:2 2314:( 2311:c 2308:+ 2305:) 2300:3 2295:+ 2290:2 2285:( 2282:b 2279:+ 2276:a 2272:{ 2268:= 2258:) 2253:3 2248:+ 2243:2 2238:( 2234:Q 2230:= 2223:) 2218:3 2213:, 2208:2 2203:( 2199:Q 2171:, 2167:Q 2146:) 2141:2 2136:( 2132:Q 2104:, 2100:} 2095:Q 2088:d 2085:, 2082:c 2079:, 2076:b 2073:, 2070:a 2062:6 2057:d 2054:+ 2049:3 2044:c 2041:+ 2036:2 2031:b 2028:+ 2025:a 2021:{ 2017:= 2006:} 2001:) 1996:2 1991:( 1986:Q 1979:b 1976:, 1973:a 1965:3 1960:b 1957:+ 1954:a 1950:{ 1946:= 1935:) 1930:3 1925:( 1920:) 1915:2 1910:( 1905:Q 1901:= 1893:) 1887:3 1882:, 1877:2 1871:( 1866:Q 1834:} 1828:2 1823:, 1820:1 1816:{ 1795:, 1791:Q 1767:, 1763:} 1758:Q 1751:b 1748:, 1745:a 1737:2 1732:b 1729:+ 1726:a 1722:{ 1718:= 1715:) 1710:2 1705:( 1701:Q 1668:c 1663:= 1660:] 1656:Q 1652:: 1648:R 1644:[ 1625:. 1622:) 1619:i 1616:( 1612:R 1608:= 1604:C 1582:R 1577:/ 1572:C 1551:} 1548:i 1545:, 1542:1 1539:{ 1519:2 1516:= 1513:] 1509:R 1505:: 1501:C 1497:[ 1476:Q 1471:/ 1466:C 1444:Q 1422:R 1400:R 1375:C 1326:K 1324:: 1322:L 1310:K 1306:L 1294:K 1290:s 1282:s 1280:( 1278:K 1273:K 1269:s 1267:( 1265:K 1246:K 1242:S 1230:) 1228:S 1226:( 1224:K 1212:s 1203:K 1199:s 1197:( 1195:K 1190:s 1186:S 1182:K 1172:S 1170:( 1168:K 1154:, 1151:) 1148:} 1143:n 1139:x 1135:, 1129:, 1124:1 1120:x 1116:{ 1113:( 1110:K 1090:) 1085:n 1081:x 1077:, 1071:, 1066:1 1062:x 1058:( 1055:K 1035:} 1030:n 1026:x 1022:, 1016:, 1011:1 1007:x 1003:{ 1000:= 997:S 987:K 983:S 981:( 979:K 971:S 967:K 963:S 955:S 953:( 951:K 947:S 937:K 933:S 931:( 929:K 925:S 921:K 917:L 913:S 909:K 905:L 901:L 897:S 883:K 879:/ 875:L 852:. 849:] 846:K 843:: 840:L 837:[ 831:] 828:L 825:: 822:M 819:[ 816:= 813:] 810:K 807:: 804:M 801:[ 778:L 774:/ 770:M 750:K 746:/ 742:L 722:K 718:/ 714:M 694:L 690:/ 686:M 666:K 662:/ 658:L 612:] 609:K 606:: 603:L 600:[ 577:- 575:K 571:L 557:K 553:/ 549:L 526:K 522:/ 518:L 496:F 492:K 488:F 484:L 477:K 473:L 459:K 455:/ 451:L 437:K 425:L 421:L 417:K 388:0 350:L 330:K 303:K 275:1 255:L 235:L 229:K 206:L 183:K 127:L 119:K 115:K 107:L 103:K 96:L 92:K 78:L 72:K 49:K 45:/ 41:L

Index

mathematics
algebra
fields
restricted
addition
multiplication
complex numbers
real numbers
algebraic number theory
polynomial roots
Galois theory
algebraic geometry
field
subset
closed
inverse
rational numbers
real numbers
isomorphic
characteristic
characteristic
vector space
dimension
degree of the extension
generating set
simple extension
primitive element
characteristic
primitive element theorem
rational fractions

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