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Lagrange number

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132: 316: 414: 152:
by any larger number in the above expression then we will only be able to find finitely many rational numbers that satisfy the inequality for α = φ.
551: 62: 48:'s criterion on irrationality to the statement that a real number α is irrational if and only if there are infinitely many rational numbers 33: 575: 518: 255: 45: 478: 548: 350: 227: 559: 494: 25: 155:
However, Hurwitz also showed that if we omit the number φ, and numbers derived from it, then we
514: 542: 482: 470: 29: 555: 510: 486: 498: 173:. Again this new bound is best possible in the new setting, but this time the number 569: 333: 127:{\displaystyle \left|\alpha -{\frac {p}{q}}\right|<{\frac {1}{{\sqrt {5}}q^{2}}}.} 503: 534: 142: 24:
are a sequence of numbers that appear in bounds relating to the approximation of
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then we can increase the number on the right hand side of the inequality from 2
538: 477:. Cambridge Tracts in Mathematics and Mathematical Physics. Vol. 45. 141:
on the right hand side. The above result is best possible since the
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Introduction to Diophantine methods irrationality and transcendence
201:/5. Repeating this process we get an infinite sequence of numbers 311:{\displaystyle L_{n}={\sqrt {9-{\frac {4}{{m_{n}}^{2}}}}}} 222:/5, ... which converge to 3. These numbers are called the 137:
This was an improvement on Dirichlet's result which had 1/
353: 258: 65: 502: 408: 310: 126: 8: 475:An introduction to Diophantine approximation 166:. In fact he showed we may replace it with 2 405: 384: 371: 358: 352: 298: 291: 286: 280: 272: 263: 257: 112: 101: 95: 77: 64: 409:{\displaystyle m^{2}+x^{2}+y^{2}=3mxy\,} 436: 562:, Lagrange Numbers on pp. 24–26. 56:, written in lowest terms, such that 7: 419:has a solution in positive integers 180:is the problem. If we don't allow 145:φ is irrational but if we replace 14: 452:Conway&Guy (1996) pp.187-189 46:Peter Gustav Lejeune Dirichlet 1: 592: 558:- Online lecture notes by 479:Cambridge University Press 234:Relation to Markov numbers 576:Diophantine approximation 344:such that the equation 410: 312: 226:, and are named after 128: 32:. They are linked to 411: 313: 228:Joseph Louis Lagrange 129: 351: 340:th smallest integer 256: 159:increase the number 63: 505:The Book of Numbers 461:Cassels (1957) p.41 443:Cassels (1957) p.14 242:th Lagrange number 560:Michel Waldschmidt 554:2012-02-09 at the 406: 308: 124: 26:irrational numbers 306: 304: 119: 106: 85: 44:Hurwitz improved 34:Hurwitz's theorem 583: 543:Wolfram Research 524: 508: 490: 462: 459: 453: 450: 444: 441: 415: 413: 412: 407: 389: 388: 376: 375: 363: 362: 317: 315: 314: 309: 307: 305: 303: 302: 297: 296: 295: 281: 273: 268: 267: 224:Lagrange numbers 221: 220: 214: 213: 207: 206: 200: 199: 193: 192: 186: 185: 179: 178: 172: 171: 165: 164: 151: 150: 133: 131: 130: 125: 120: 118: 117: 116: 107: 102: 96: 91: 87: 86: 78: 30:rational numbers 22:Lagrange numbers 591: 590: 586: 585: 584: 582: 581: 580: 566: 565: 556:Wayback Machine 535:Lagrange number 531: 521: 511:Springer-Verlag 493: 471:Cassels, J.W.S. 469: 466: 465: 460: 456: 451: 447: 442: 438: 433: 380: 367: 354: 349: 348: 326: 287: 285: 259: 254: 253: 247: 236: 218: 216: 211: 209: 204: 202: 197: 195: 190: 188: 183: 181: 176: 174: 169: 167: 162: 160: 148: 146: 108: 100: 70: 66: 61: 60: 42: 12: 11: 5: 589: 587: 579: 578: 568: 567: 564: 563: 546: 530: 529:External links 527: 526: 525: 519: 491: 464: 463: 454: 445: 435: 434: 432: 429: 417: 416: 404: 401: 398: 395: 392: 387: 383: 379: 374: 370: 366: 361: 357: 336:, that is the 324: 319: 318: 301: 294: 290: 284: 279: 276: 271: 266: 262: 245: 235: 232: 135: 134: 123: 115: 111: 105: 99: 94: 90: 84: 81: 76: 73: 69: 41: 38: 13: 10: 9: 6: 4: 3: 2: 588: 577: 574: 573: 571: 561: 557: 553: 550: 547: 544: 540: 536: 533: 532: 528: 522: 520:0-387-97993-X 516: 512: 507: 506: 500: 496: 492: 488: 484: 480: 476: 472: 468: 467: 458: 455: 449: 446: 440: 437: 430: 428: 426: 422: 402: 399: 396: 393: 390: 385: 381: 377: 372: 368: 364: 359: 355: 347: 346: 345: 343: 339: 335: 334:Markov number 331: 327: 299: 292: 288: 282: 277: 274: 269: 264: 260: 252: 251: 250: 248: 241: 233: 231: 229: 225: 158: 153: 144: 140: 121: 113: 109: 103: 97: 92: 88: 82: 79: 74: 71: 67: 59: 58: 57: 55: 51: 47: 39: 37: 35: 31: 27: 23: 19: 509:. New York: 504: 495:Conway, J.H. 474: 457: 448: 439: 424: 420: 418: 341: 337: 329: 322: 320: 249:is given by 243: 239: 237: 223: 156: 154: 143:golden ratio 138: 136: 53: 49: 43: 21: 15: 18:mathematics 487:0077.04801 431:References 40:Definition 539:MathWorld 499:Guy, R.K. 278:− 75:− 72:α 570:Category 552:Archived 537:. From 501:(1996). 473:(1957). 328:is the 217:√ 210:√ 203:√ 196:√ 189:√ 182:√ 175:√ 168:√ 161:√ 147:√ 517:  485:  321:where 20:, the 515:ISBN 423:and 238:The 93:< 541:at 483:Zbl 332:th 219:221 208:, 2 198:221 194:to 157:can 28:by 16:In 572:: 513:. 497:; 481:. 427:. 230:. 215:, 36:. 545:. 523:. 489:. 425:y 421:x 403:y 400:x 397:m 394:3 391:= 386:2 382:y 378:+ 373:2 369:x 365:+ 360:2 356:m 342:m 338:n 330:n 325:n 323:m 300:2 293:n 289:m 283:4 275:9 270:= 265:n 261:L 246:n 244:L 240:n 212:2 205:5 191:2 184:2 177:2 170:2 163:5 149:5 139:q 122:. 114:2 110:q 104:5 98:1 89:| 83:q 80:p 68:| 54:q 52:/ 50:p

Index

mathematics
irrational numbers
rational numbers
Hurwitz's theorem
Peter Gustav Lejeune Dirichlet
golden ratio
Joseph Louis Lagrange
Markov number
Cassels, J.W.S.
Cambridge University Press
Zbl
0077.04801
Conway, J.H.
Guy, R.K.
The Book of Numbers
Springer-Verlag
ISBN
0-387-97993-X
Lagrange number
MathWorld
Wolfram Research
Introduction to Diophantine methods irrationality and transcendence
Archived
Wayback Machine
Michel Waldschmidt
Category
Diophantine approximation

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