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Topologist's sine curve

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20: 197: 390:; some texts define the topologist's sine curve itself as this closed version, as they prefer to use the term 'closed topologist's sine curve' to refer to another curve. This space is closed and bounded and so 465: 388: 84: 555: 398:, but has similar properties to the topologist's sine curve—it too is connected but neither locally connected nor path-connected. 518: 600: 542: 226:. This is because it includes the point (0,0) but there is no way to link the function to the origin so as to make a 395: 472: 219: 537: 408: 328: 299: 31:
increases. This is why the frequency of the sine wave increases as one moves to the left in the graph.
59: 547: 484: 67: 573: 551: 533: 514: 192:{\displaystyle T=\left\{\left(x,\sin {\tfrac {1}{x}}\right):x\in (0,1]\right\}\cup \{(0,0)\}.} 71: 52: 565: 19: 576: 561: 238: 227: 223: 215: 75: 594: 489: 468: 405:
can be defined by taking the closed topologist's sine curve and adding to it the set
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reprint of 1978 ed.), Mineola, NY: Dover Publications, Inc., pp. 137–138,
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with several interesting properties that make it an important textbook example.
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Two variants of the topologist's sine curve have other interesting properties.
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can be defined by taking the topologist's sine curve and adding its set of
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approaches zero from the right, the magnitude of the rate of change of 1/
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be the space {−1} ∪ (0, 1], and use the map
70:(0, 1], together with the origin, under the topology 117: 411: 331: 87: 459: 382: 191: 8: 454: 412: 377: 332: 183: 165: 410: 330: 116: 86: 18: 501: 7: 460:{\displaystyle \{(x,1)\mid x\in \}} 383:{\displaystyle \{(0,y)\mid y\in \}} 14: 513:. Englewood Cliffs. p. 158. 403:extended topologist's sine curve 295:is not locally compact itself. 451: 439: 427: 415: 374: 359: 347: 335: 319:closed topologist's sine curve 180: 168: 154: 142: 16:Pathological topological space 1: 237:is the continuous image of a 210:The topologist's sine curve 543:Counterexamples in Topology 617: 577:"Topologist's Sine Curve" 509:Munkres, James R (1979). 58:It can be defined as the 511:Topology; a First Course 45:topologist's sine curve 538:Seebach, J. Arthur Jr. 461: 384: 193: 62:of the function sin(1/ 32: 462: 385: 300:topological dimension 194: 22: 409: 329: 85: 396:Heine–Borel theorem 241:space (namely, let 601:Topological spaces 574:Weisstein, Eric W. 534:Steen, Lynn Arthur 485:List of topologies 457: 380: 189: 126: 68:half-open interval 33: 557:978-0-486-68735-3 473:locally connected 220:locally connected 125: 53:topological space 49:Warsaw sine curve 35:In the branch of 608: 587: 586: 568: 525: 524: 506: 466: 464: 463: 458: 389: 387: 386: 381: 286: 274: 263: 198: 196: 195: 190: 161: 157: 132: 128: 127: 118: 616: 615: 611: 610: 609: 607: 606: 605: 591: 590: 572: 571: 558: 532: 529: 528: 521: 508: 507: 503: 498: 481: 407: 406: 327: 326: 312: 276: 265: 258: 239:locally compact 208: 202: 103: 99: 98: 94: 83: 82: 76:Euclidean plane 17: 12: 11: 5: 614: 612: 604: 603: 593: 592: 589: 588: 569: 556: 527: 526: 519: 500: 499: 497: 494: 493: 492: 487: 480: 477: 456: 453: 450: 447: 444: 441: 438: 435: 432: 429: 426: 423: 420: 417: 414: 379: 376: 373: 370: 367: 364: 361: 358: 355: 352: 349: 346: 343: 340: 337: 334: 311: 308: 224:path connected 207: 204: 200: 199: 188: 185: 182: 179: 176: 173: 170: 167: 164: 160: 156: 153: 150: 147: 144: 141: 138: 135: 131: 124: 121: 115: 112: 109: 106: 102: 97: 93: 90: 15: 13: 10: 9: 6: 4: 3: 2: 613: 602: 599: 598: 596: 584: 583: 578: 575: 570: 567: 563: 559: 553: 549: 545: 544: 539: 535: 531: 530: 522: 520:9780139254956 516: 512: 505: 502: 495: 491: 490:Warsaw circle 488: 486: 483: 482: 478: 476: 474: 470: 469:arc connected 448: 445: 442: 436: 433: 430: 424: 421: 418: 404: 399: 397: 393: 371: 368: 365: 362: 356: 353: 350: 344: 341: 338: 324: 320: 315: 309: 307: 305: 301: 296: 294: 291:> 0), but 290: 284: 281:, sin(1/ 280: 272: 268: 261: 256: 252: 248: 244: 240: 236: 231: 229: 225: 221: 217: 213: 205: 203: 186: 177: 174: 171: 162: 158: 151: 148: 145: 139: 136: 133: 129: 122: 119: 113: 110: 107: 104: 100: 95: 91: 88: 81: 80: 79: 77: 73: 69: 65: 61: 56: 54: 50: 46: 42: 38: 30: 26: 21: 580: 541: 510: 504: 402: 400: 323:limit points 318: 316: 313: 303: 297: 292: 288: 282: 278: 270: 266: 264:= (0,0) and 259: 254: 250: 246: 242: 234: 232: 218:but neither 211: 209: 201: 63: 57: 48: 44: 34: 28: 24: 257:defined by 37:mathematics 496:References 262:(−1) 233:The space 206:Properties 582:MathWorld 540:(1995) , 437:∈ 431:∣ 363:− 357:∈ 351:∣ 216:connected 163:∪ 140:∈ 114:⁡ 74:from the 66:) on the 39:known as 595:Category 479:See also 471:but not 467:. It is 310:Variants 41:topology 566:1382863 394:by the 392:compact 72:induced 564:  554:  517:  306:is 1. 43:, the 548:Dover 249:from 60:graph 51:is a 552:ISBN 515:ISBN 401:The 317:The 298:The 287:for 228:path 222:nor 302:of 253:to 214:is 111:sin 47:or 23:As 597:: 579:. 562:MR 560:, 536:; 475:. 325:, 285:)) 275:= 230:. 78:: 585:. 546:( 523:. 455:} 452:] 449:1 446:, 443:0 440:[ 434:x 428:) 425:1 422:, 419:x 416:( 413:{ 378:} 375:] 372:1 369:, 366:1 360:[ 354:y 348:) 345:y 342:, 339:0 336:( 333:{ 304:T 293:T 289:x 283:x 279:x 277:( 273:) 271:x 269:( 267:f 260:f 255:T 251:V 247:f 243:V 235:T 212:T 187:. 184:} 181:) 178:0 175:, 172:0 169:( 166:{ 159:} 155:] 152:1 149:, 146:0 143:( 137:x 134:: 130:) 123:x 120:1 108:, 105:x 101:( 96:{ 92:= 89:T 64:x 29:x 25:x

Index


mathematics
topology
topological space
graph
half-open interval
induced
Euclidean plane
connected
locally connected
path connected
path
locally compact
topological dimension
limit points
compact
Heine–Borel theorem
arc connected
locally connected
List of topologies
Warsaw circle
ISBN
9780139254956
Steen, Lynn Arthur
Seebach, J. Arthur Jr.
Counterexamples in Topology
Dover
ISBN
978-0-486-68735-3
MR

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