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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.
97:. 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 159: 410:, 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 17: 435: 77: 480: 99: 125:
Burnside's problem is a classical question that deals with the relationship between periodic groups and
320: 273:{\displaystyle \forall x,{\big (}(x=e)\lor (x\circ x=e)\lor ((x\circ x)\circ x=e)\lor \cdots {\big )},} 337: 149:
An interesting property of periodic groups is that the definition cannot be formalized in terms of
130: 427: 421: 107:. These groups have infinite exponent; examples with finite exponent are given for instance by 31: 316: 120: 70: 58: 108: 8: 407: 323:
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
90: 30:"Periodic group" redirects here. For groups in the chemical periodic table, see 94: 474: 305: 138: 126: 62: 38: 42: 141:, the answer to Burnside's problem restricted to the class is positive. 319:
is an abelian group in which every element has finite order. A
153:. This is because doing so would require an axiom of the form 375:
Finite automata and the Burnside problem for periodic groups
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groups there are still some for which the problem is open.
426:(2. ed., 4. pr. ed.). New York : Springer. pp.  315:
that consists of all elements that have finite order. A
162: 419: 358:On nil-algebras and finitely approximable p-groups 272: 472: 420:Ebbinghaus, H.-D.; Flum, J.; Thomas, W. (1994). 262: 174: 27:Group in which each element has finite order 93:. Another example is the direct sum of all 137:For some classes of groups, for instance 392:On Burnside's problem on periodic groups 103:), and by Aleshin and Grigorchuk using 14: 473: 69:of such a group, if it exists, is the 144: 114: 83: 24: 295: 163: 25: 492: 463:, Izv. Akad. Nauk SSSR Ser. Mat. 360:, Izv. Akad. Nauk SSSR Ser. Mat. 73:of the orders of the elements. 413: 401: 384: 367: 350: 251: 236: 224: 221: 215: 197: 191: 179: 13: 1: 343: 76:For example, it follows from 7: 326: 283:which contains an infinite 111:constructed by Olshanskii. 10: 497: 467:(1984), 939–985 (Russian). 321:torsion-free abelian group 118: 29: 394:, Functional Anal. Appl. 377:, (Russian) Mat. Zametki 131:finitely generated groups 100:Golod–Shafarevich theorem 18:Exponent (group theory) 274: 32:Group (periodic table) 398:(1980), no. 1, 41–43. 317:torsion abelian group 275: 109:Tarski monster groups 71:least common multiple 481:Properties of groups 338:Jordan–Schur theorem 160: 311:is the subgroup of 290:compactness theorem 459:R. I. Grigorchuk, 423:Mathematical logic 390:R. I. Grigorchuk, 270: 145:Mathematical logic 121:Burnside's problem 115:Burnside's problem 78:Lagrange's theorem 437:978-0-387-94258-2 408:A. Yu. Olshanskii 333:Torsion (algebra) 151:first-order logic 84:Infinite examples 16:(Redirected from 488: 452: 451: 446: 444: 417: 411: 405: 399: 388: 382: 381:(1972), 319–328. 371: 365: 354: 302:torsion subgroup 279: 277: 276: 271: 266: 265: 178: 177: 21: 496: 495: 491: 490: 489: 487: 486: 485: 471: 470: 456: 455: 442: 440: 438: 418: 414: 406: 402: 389: 385: 373:S. V. Aleshin, 372: 368: 364:(1964) 273–276. 355: 351: 346: 329: 298: 296:Related notions 261: 260: 173: 172: 161: 158: 157: 147: 123: 117: 95:dihedral groups 86: 57:in which every 35: 28: 23: 22: 15: 12: 11: 5: 494: 484: 483: 469: 468: 454: 453: 436: 412: 400: 383: 366: 348: 347: 345: 342: 341: 340: 335: 328: 325: 297: 294: 281: 280: 269: 264: 259: 256: 253: 250: 247: 244: 241: 238: 235: 232: 229: 226: 223: 220: 217: 214: 211: 208: 205: 202: 199: 196: 193: 190: 187: 184: 181: 176: 171: 168: 165: 146: 143: 119:Main article: 116: 113: 85: 82: 51:periodic group 41:, a branch of 26: 9: 6: 4: 3: 2: 493: 482: 479: 478: 476: 466: 462: 458: 457: 450: 439: 433: 429: 425: 424: 416: 409: 404: 397: 393: 387: 380: 376: 370: 363: 359: 356:E. S. Golod, 353: 349: 339: 336: 334: 331: 330: 324: 322: 318: 314: 310: 307: 306:abelian group 303: 293: 291: 286: 267: 257: 254: 248: 245: 242: 239: 233: 230: 227: 218: 212: 209: 206: 203: 200: 194: 188: 185: 182: 169: 166: 156: 155: 154: 152: 142: 140: 139:linear groups 135: 132: 128: 127:finite groups 122: 112: 110: 106: 102: 101: 96: 92: 91:PrĂĽfer groups 81: 79: 74: 72: 68: 64: 60: 56: 52: 48: 47:torsion group 44: 40: 33: 19: 464: 460: 448: 441:. Retrieved 422: 415: 403: 395: 391: 386: 378: 374: 369: 361: 357: 352: 312: 308: 299: 282: 148: 136: 129:, when only 124: 98: 87: 75: 66: 63:finite order 50: 46: 39:group theory 36: 285:disjunction 43:mathematics 344:References 258:⋯ 255:∨ 240:∘ 231:∘ 219:∨ 204:∘ 195:∨ 164:∀ 475:Category 327:See also 105:automata 67:exponent 443:18 July 59:element 434:  304:of an 65:. The 55:group 53:is a 49:or a 465:48:5 445:2012 432:ISBN 300:The 61:has 45:, a 37:In 477:: 447:. 430:. 428:50 396:14 379:11 362:28 313:A 309:A 268:, 263:) 252:) 249:e 246:= 243:x 237:) 234:x 228:x 225:( 222:( 216:) 213:e 210:= 207:x 201:x 198:( 192:) 189:e 186:= 183:x 180:( 175:( 170:, 167:x 34:. 20:)

Index

Exponent (group theory)
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
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