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Torsion group

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are considered: Does specifying an exponent force finiteness? The existence of infinite, finitely generated periodic groups as in the previous paragraph shows that the answer is "no" for an arbitrary exponent. Though much more is known about which exponents can occur for infinite finitely generated
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and is therefore inadmissible: first order logic permits quantifiers over one type and cannot capture properties or subsets of that type. It is also not possible to get around this infinite disjunction by using an infinite set of axioms: the
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Examples of infinite periodic groups include the additive group of the ring of polynomials over a finite field, and the quotient group of the rationals by the integers, as well as their direct summands, the
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However, in first-order logic we may not form infinitely long disjunctions. Indeed, we shall later show that there is no set of first-order formulas whose models are precisely the periodic groups.
86:. None of these examples has a finite generating set. Explicit examples of finitely generated infinite periodic groups were constructed by Golod, based on joint work with Shafarevich (see 148: 399:, An infinite group with subgroups of prime orders, Math. USSR Izv. 16 (1981), 279–289; translation of Izvestia Akad. Nauk SSSR Ser. Matem. 44 (1980), 309–321 424: 66: 469: 88: 114:
Burnside's problem is a classical question that deals with the relationship between periodic groups and
309: 262:{\displaystyle \forall x,{\big (}(x=e)\lor (x\circ x=e)\lor ((x\circ x)\circ x=e)\lor \cdots {\big )},} 326: 138:
An interesting property of periodic groups is that the definition cannot be formalized in terms of
119: 416: 410: 96:. These groups have infinite exponent; examples with finite exponent are given for instance by 20: 305: 109: 59: 47: 97: 8: 396: 312:
is an abelian group in which the identity element is the only element with finite order.
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that every finite group is periodic and it has an exponent that divides its order.
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implies that no set of first-order formulae can characterize the periodic groups.
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Degrees of growth of finitely generated groups and the theory of invariant means
79: 19:"Periodic group" redirects here. For groups in the chemical periodic table, see 83: 463: 294: 127: 115: 51: 27: 31: 130:, the answer to Burnside's problem restricted to the class is positive. 308:
is an abelian group in which every element has finite order. A
142:. This is because doing so would require an axiom of the form 364:
Finite automata and the Burnside problem for periodic groups
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groups there are still some for which the problem is open.
415:(2. ed., 4. pr. ed.). New York : Springer. pp.  304:
that consists of all elements that have finite order. A
151: 408: 347:On nil-algebras and finitely approximable p-groups 261: 461: 409:Ebbinghaus, H.-D.; Flum, J.; Thomas, W. (1994). 251: 163: 16:Group in which each element has finite order 82:. Another example is the direct sum of all 126:For some classes of groups, for instance 381:On Burnside's problem on periodic groups 92:), and by Aleshin and Grigorchuk using 462: 58:of such a group, if it exists, is the 133: 103: 72: 13: 284: 152: 14: 481: 452:, Izv. Akad. Nauk SSSR Ser. Mat. 349:, Izv. Akad. Nauk SSSR Ser. Mat. 62:of the orders of the elements. 402: 390: 373: 356: 339: 240: 225: 213: 210: 204: 186: 180: 168: 1: 332: 65:For example, it follows from 7: 315: 272:which contains an infinite 100:constructed by Olshanskii. 10: 486: 456:(1984), 939–985 (Russian). 310:torsion-free abelian group 107: 18: 383:, Functional Anal. Appl. 366:, (Russian) Mat. Zametki 120:finitely generated groups 89:Golod–Shafarevich theorem 263: 21:Group (periodic table) 387:(1980), no. 1, 41–43. 306:torsion abelian group 264: 98:Tarski monster groups 60:least common multiple 470:Properties of groups 327:Jordan–Schur theorem 149: 300:is the subgroup of 279:compactness theorem 448:R. I. Grigorchuk, 412:Mathematical logic 379:R. I. Grigorchuk, 259: 134:Mathematical logic 110:Burnside's problem 104:Burnside's problem 67:Lagrange's theorem 426:978-0-387-94258-2 397:A. Yu. Olshanskii 322:Torsion (algebra) 140:first-order logic 73:Infinite examples 477: 441: 440: 435: 433: 406: 400: 394: 388: 377: 371: 370:(1972), 319–328. 360: 354: 343: 291:torsion subgroup 268: 266: 265: 260: 255: 254: 167: 166: 485: 484: 480: 479: 478: 476: 475: 474: 460: 459: 445: 444: 431: 429: 427: 407: 403: 395: 391: 378: 374: 362:S. V. Aleshin, 361: 357: 353:(1964) 273–276. 344: 340: 335: 318: 287: 285:Related notions 250: 249: 162: 161: 150: 147: 146: 136: 112: 106: 84:dihedral groups 75: 46:in which every 24: 17: 12: 11: 5: 483: 473: 472: 458: 457: 443: 442: 425: 401: 389: 372: 355: 337: 336: 334: 331: 330: 329: 324: 317: 314: 286: 283: 270: 269: 258: 253: 248: 245: 242: 239: 236: 233: 230: 227: 224: 221: 218: 215: 212: 209: 206: 203: 200: 197: 194: 191: 188: 185: 182: 179: 176: 173: 170: 165: 160: 157: 154: 135: 132: 108:Main article: 105: 102: 74: 71: 40:periodic group 30:, a branch of 15: 9: 6: 4: 3: 2: 482: 471: 468: 467: 465: 455: 451: 447: 446: 439: 428: 422: 418: 414: 413: 405: 398: 393: 386: 382: 376: 369: 365: 359: 352: 348: 345:E. S. Golod, 342: 338: 328: 325: 323: 320: 319: 313: 311: 307: 303: 299: 296: 295:abelian group 292: 282: 280: 275: 256: 246: 243: 237: 234: 231: 228: 222: 219: 216: 207: 201: 198: 195: 192: 189: 183: 177: 174: 171: 158: 155: 145: 144: 143: 141: 131: 129: 128:linear groups 124: 121: 117: 116:finite groups 111: 101: 99: 95: 91: 90: 85: 81: 80:PrĂĽfer groups 70: 68: 63: 61: 57: 53: 49: 45: 41: 37: 36:torsion group 33: 29: 22: 453: 449: 437: 430:. Retrieved 411: 404: 392: 384: 380: 375: 367: 363: 358: 350: 346: 341: 301: 297: 288: 271: 137: 125: 118:, when only 113: 87: 76: 64: 55: 52:finite order 39: 35: 28:group theory 25: 274:disjunction 32:mathematics 333:References 247:⋯ 244:∨ 229:∘ 220:∘ 208:∨ 193:∘ 184:∨ 153:∀ 464:Category 316:See also 94:automata 56:exponent 432:18 July 48:element 423:  293:of an 54:. The 44:group 42:is a 38:or a 454:48:5 434:2012 421:ISBN 289:The 50:has 34:, a 26:In 466:: 436:. 419:. 417:50 385:14 368:11 351:28 302:A 298:A 257:, 252:) 241:) 238:e 235:= 232:x 226:) 223:x 217:x 214:( 211:( 205:) 202:e 199:= 196:x 190:x 187:( 181:) 178:e 175:= 172:x 169:( 164:( 159:, 156:x 23:.

Index

Group (periodic table)
group theory
mathematics
group
element
finite order
least common multiple
Lagrange's theorem
PrĂĽfer groups
dihedral groups
Golod–Shafarevich theorem
automata
Tarski monster groups
Burnside's problem
finite groups
finitely generated groups
linear groups
first-order logic
disjunction
compactness theorem
torsion subgroup
abelian group
torsion abelian group
torsion-free abelian group
Torsion (algebra)
Jordan–Schur theorem
A. Yu. Olshanskii
Mathematical logic
50
ISBN

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