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Projectively extended real line

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2577: 2143: 2572:{\displaystyle {\begin{aligned}\left&=\lbrace x\mid x\in \mathbb {R} ,a\leq x\leq b\rbrace \\\left&=\lbrace x\mid x\in \mathbb {R} ,a\leq x\rbrace \cup \lbrace \infty \rbrace \\\left&=\lbrace x\mid x\in \mathbb {R} ,b\leq x\rbrace \cup \lbrace \infty \rbrace \cup \lbrace x\mid x\in \mathbb {R} ,x\leq a\rbrace \\\left&=\lbrace \infty \rbrace \cup \lbrace x\mid x\in \mathbb {R} ,x\leq a\rbrace \\\left&=\{a\}\\\left&=\lbrace \infty \rbrace \end{aligned}}} 1255: 148: 937: 51: 1990: 1250:{\displaystyle {\begin{aligned}a+\infty =\infty +a&=\infty ,&a\neq \infty \\a-\infty =\infty -a&=\infty ,&a\neq \infty \\a/\infty =a\cdot 0=0\cdot a&=0,&a\neq \infty \\\infty /a&=\infty ,&a\neq \infty \\a/0=a\cdot \infty =\infty \cdot a&=\infty ,&a\neq 0\\0/a&=0,&a\neq 0\end{aligned}}} 1721: 5291: 1376: 1783: 1265:
The following expressions cannot be motivated by considering limits of real functions, and no definition of them allows the statement of the standard algebraic properties to be retained unchanged in form for all defined cases. Consequently, they are left undefined:
2840: 1511: 5588: 5173: 6190: 4003: 1272: 3007:. The result of an arithmetic operation on intervals is always an interval, except when the intervals with a binary operation contain incompatible values leading to an undefined result. In particular, we have, for every 3615: 1985:{\displaystyle {\begin{aligned}a\cdot (b+c)&=a\cdot b+a\cdot c\\a&=\left({\frac {a}{b}}\right)\cdot b&=\,\,&{\frac {(a\cdot b)}{b}}\\a&=(a+b)-b&=\,\,&(a-b)+b\end{aligned}}} 7106: 5050: 4981: 4920: 4851: 5724: 6609: 5095: 3280: 3144: 2148: 1788: 1776: 1516: 1504: 1277: 942: 6980: 5770: 4614: 4497: 3048: 4790: 3654: 3691: 3243: 929: 4670: 4553: 4724: 249: 6645: 6514: 6937: 6334: 6272: 6032: 5681: 4261: 4201: 2135: 312: 7031: 6810: 6479: 5998: 5967: 3198: 2983: 2694: 2652: 2617: 2089: 2046: 1716:{\displaystyle {\begin{aligned}(a+b)+c&=a+(b+c)\\a+b&=b+a\\(a\cdot b)\cdot c&=a\cdot (b\cdot c)\\a\cdot b&=b\cdot a\\a\cdot \infty &={\frac {a}{0}}\\\end{aligned}}} 1440: 892: 670: 617: 561: 6550: 5497: 5454: 4436: 4383: 4141: 3776: 2725: 2582:
With the exception of when the end-points are equal, the corresponding open and half-open intervals are defined by removing the respective endpoints. This redefinition is useful in
419: 6880: 5512: 4327: 2874: 811: 278: 6419: 6371: 6238: 2942: 7000: 6572: 6300: 5371: 5286:{\displaystyle f:{\widehat {\mathbb {R} }}\to {\widehat {\mathbb {R} }},A\subseteq {\widehat {\mathbb {R} }},L\in {\widehat {\mathbb {R} }},p\in {\widehat {\mathbb {R} }}} 4287: 3508: 3005: 2720: 2015: 861: 639: 211: 3540: 5409: 4086: 3856: 6442: 6394: 6118: 6079: 5166: 68: 6056: 3429: 3353: 2903: 5805: 5137: 4048: 3821: 7138: 7063: 6213: 6110: 5896: 3465: 3389: 1409: 5846: 2091:. However, since it is not an ordered set, the interval has a slightly different meaning. The definitions for closed intervals are as follows (it is assumed that 1371:{\displaystyle {\begin{aligned}&\infty +\infty \\&\infty -\infty \\&\infty \cdot 0\\&0\cdot \infty \\&\infty /\infty \\&0/0\end{aligned}}} 7199: 3891: 7293: 7240: 3563: 115: 7303: 719:(also called linear fractional transformations), with the understanding that when the denominator of the linear fractional transformation is 87: 6482: 94: 826:
The arithmetic operations on this space are an extension of the same operations on reals. A motivation for the new definitions is the
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on this circle (either measured straight or along the circle). There is no metric which is an extension of the ordinary metric on
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The definitions given above can be compared with the usual definitions of limits of real functions. In the following statements,
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relation between points is part of the structure of the real projective line. For instance, given any pair of points, the
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is undefined, even though the reciprocal is total. It has usable interpretations, however – for example, in geometry, the
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An extension does however exist in which all the algebraic properties, when restricted to defined operations in
6305: 6243: 6003: 5621: 4206: 4146: 2094: 283: 7005: 6784: 6757: 6724: 6453: 5972: 5941: 3172: 2957: 2835:{\displaystyle (b,a)=\{x\mid x\in \mathbb {R} ,b<x\}\cup \{\infty \}\cup \{x\mid x\in \mathbb {R} ,x<a\}} 2668: 2626: 2591: 2063: 2020: 1414: 866: 778: 644: 591: 535: 156: 6519: 5583:{\displaystyle f:{\widehat {\mathbb {R} }}\to {\widehat {\mathbb {R} }},\quad p\in {\widehat {\mathbb {R} }}.} 5467: 5424: 716: 108: 6341: 4388: 4335: 4093: 3728: 3474: 391: 61: 6828: 7325: 6740: 4295: 2057: 440: 437: 2845: 6752: 6670: 5414: 6674: 787: 254: 6666: 6612: 6337: 2916: 1382: 704: 697: 346: 30:
This article is about the extension of the reals by a single point at infinity. For the extension by
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can't be compared with any of the other elements, there's no point in retaining this relation on
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The projectively extended real line can be visualized as the real number line wrapped around a
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with the standard arithmetic operations extended where possible, and is sometimes denoted by
6736: 6735:. Two of these correspond to elementary, arithmetic operations on the real projective line: 6660: 6089: 5784: 5116: 4027: 3800: 2697: 458: 382: 339: 7111: 7036: 6396:
As seen above, the tangent function can be prolongated to a function that is continuous in
6198: 6095: 5869: 3438: 3362: 1387: 6743:. Indeed, 0 and ∞ are fixed under negation, while 1 and βˆ’1 are fixed under reciprocation. 5822: 3862: 2658: 781: 774: 3998:{\displaystyle \lim _{x\to p^{+}}{f(x)}=L\qquad \left(\lim _{x\to p^{-}}{f(x)}=L\right),} 766:
on the real projective line. This cannot be extended to 4-tuples of points, because the
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the first limit is as defined above, and the second limit is in the usual sense:
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of the real projective line. The projectivities are described algebraically as
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The detailed analysis of the action shows that for any three distinct points
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is a neighbourhood (resp. a right-sided or a left-sided neighbourhood) of
6713: 6686: 6447: 3610:{\displaystyle f:{\widehat {\mathbb {R} }}\to {\widehat {\mathbb {R} }},} 3166: 1726:
The following is true whenever expressions involved are defined, for any
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is appropriate, because the points are in 1-to-1 correspondence with one-
335: 327: 6982:(where the interval on either side is defined), all intervals excluding 6240:
but cannot be prolongated further to a function that is continuous in
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is undefined, the result of division of these intervals is undefined.
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Either both sides are undefined, or both sides are defined and equal.
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Unlike most mathematical models of numbers, this structure allows
361:. The projectively extended real number line is distinct from the 146: 7268: 3477:(resp. a right-sided or a left-sided punctured neighbourhood) of 7245:. Directorate of Distance Education, University of North Bengal. 6345: 3200:. The definitions are motivated by the topology of this space. 322:
of the real line. More precisely, the point at infinity is the
4016:, there is a right-sided (left-sided) punctured neighbourhood 44: 6446:
Many discontinuous functions that become continuous when the
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in which three points have been assigned the specific values
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The projectively extended real line may be identified with a
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The projectivities which are their own inverses are called
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cannot be prolongated to functions that are continuous in
5938:, can be prolongated, in a unique way, to a function from 4266: 2915:
corresponding (for a given homeomorphism) to the ordinary
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If consistency of complementation is required, such that
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On the other hand, some functions that are continuous in
7101:{\displaystyle {\widehat {\mathbb {R} }}\setminus \{a\}} 6481:
remain discontinuous if the codomain is extended to the
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may be naturally represented using this notation, with
5045:{\displaystyle \lim _{x\to +\infty }{|f(x)|}=+\infty } 4976:{\displaystyle \lim _{x\to \infty ^{-}}{f(x)}=\infty } 4915:{\displaystyle \lim _{x\to -\infty }{|f(x)|}=+\infty } 4846:{\displaystyle \lim _{x\to \infty ^{+}}{f(x)}=\infty } 1995:
In general, all laws of arithmetic that are valid for
7155: 7114: 7108:, and half-open intervals with equal endpoints, e.g. 7071: 7039: 7008: 6988: 6945: 6888: 6831: 6787: 6677:
are implicit. In particular, the construction of the
6621: 6580: 6558: 6522: 6490: 6456: 6427: 6402: 6379: 6354: 6308: 6286: 6246: 6221: 6201: 6121: 6098: 6064: 6044: 6006: 5975: 5944: 5872: 5825: 5787: 5735: 5719:{\displaystyle A\subseteq {\widehat {\mathbb {R} }},} 5692: 5624: 5515: 5470: 5427: 5379: 5347: 5176: 5145: 5119: 5066: 4989: 4929: 4859: 4799: 4732: 4679: 4622: 4562: 4505: 4445: 4391: 4338: 4298: 4273: 4209: 4149: 4096: 4056: 4030: 3894: 3829: 3803: 3731: 3662: 3622: 3566: 3516: 3487: 3441: 3411: 3365: 3335: 3251: 3214: 3175: 3059: 3013: 2991: 2960: 2925: 2882: 2848: 2728: 2706: 2671: 2629: 2594: 2146: 2097: 2066: 2023: 2001: 1786: 1732: 1514: 1460: 1417: 1390: 1275: 940: 900: 869: 847: 790: 742:, there is a linear fractional transformation taking 647: 625: 594: 538: 394: 286: 257: 223: 197: 6604:{\displaystyle \infty \in {\widehat {\mathbb {R} }}} 5090:{\displaystyle A\subseteq {\widehat {\mathbb {R} }}} 3275:{\displaystyle A\subseteq {\widehat {\mathbb {R} }}} 3139:{\displaystyle x\in \iff {\frac {1}{x}}\in \left\!,} 2048:
whenever all the occurring expressions are defined.
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in this structure. The structure, however, is not a
1771:{\displaystyle a,b,c\in {\widehat {\mathbb {R} }}.} 1499:{\displaystyle a,b,c\in {\widehat {\mathbb {R} }}.} 570:, there is no convincing argument to define either 75:. Unsourced material may be challenged and removed. 7193: 7132: 7100: 7057: 7025: 6994: 6974: 6931: 6874: 6804: 6639: 6603: 6566: 6544: 6508: 6473: 6436: 6413: 6388: 6365: 6328: 6294: 6266: 6232: 6207: 6184: 6104: 6073: 6050: 6026: 5992: 5961: 5890: 5840: 5799: 5764: 5718: 5675: 5582: 5491: 5448: 5403: 5365: 5285: 5160: 5131: 5089: 5044: 4975: 4914: 4845: 4784: 4718: 4664: 4608: 4547: 4491: 4430: 4377: 4321: 4281: 4255: 4195: 4135: 4080: 4042: 3997: 3850: 3815: 3770: 3685: 3648: 3609: 3534: 3502: 3459: 3423: 3383: 3347: 3274: 3237: 3192: 3138: 3042: 2999: 2977: 2936: 2897: 2868: 2834: 2714: 2688: 2646: 2611: 2571: 2129: 2083: 2040: 2009: 1984: 1770: 1715: 1498: 1434: 1403: 1370: 1249: 923: 886: 855: 805: 664: 633: 611: 555: 413: 318:, because it is considered as a neighbour of both 306: 272: 243: 205: 3149:irrespective of whether either interval includes 3132: 497:, by adding a single point called conventionally 6975:{\displaystyle a,b\in {\widehat {\mathbb {R} }}} 5765:{\displaystyle f:A\to {\widehat {\mathbb {R} }}} 5626: 4991: 4931: 4861: 4801: 4734: 4681: 4624: 4609:{\displaystyle \lim _{x\to \infty ^{-}}{f(x)}=L} 4564: 4507: 4492:{\displaystyle \lim _{x\to \infty ^{+}}{f(x)}=L} 4447: 4393: 4340: 4211: 4151: 4098: 3945: 3896: 3733: 3043:{\displaystyle a,b\in {\widehat {\mathbb {R} }}} 481:The projectively extended real line extends the 7295:Geometry: from Isometries to Special Relativity 6421:but this function cannot be made continuous at 4785:{\displaystyle \lim _{x\to p}{|f(x)|}=+\infty } 3649:{\displaystyle p\in {\widehat {\mathbb {R} }},} 461:arithmetic operations are total – for example, 6696:preserve the harmonic relation, they form the 6685:is the projective harmonic conjugate of their 3686:{\displaystyle L\in {\widehat {\mathbb {R} }}} 3238:{\displaystyle x\in {\widehat {\mathbb {R} }}} 924:{\displaystyle a\in {\widehat {\mathbb {R} }}} 838:In addition to the standard operations on the 6708:, according to the general construction of a 4665:{\displaystyle \lim _{x\to +\infty }{f(x)}=L} 4548:{\displaystyle \lim _{x\to -\infty }{f(x)}=L} 1261:Arithmetic operations that are left undefined 8: 7095: 7089: 5483: 5477: 5440: 5434: 4719:{\displaystyle \lim _{x\to p}{f(x)}=\infty } 3529: 3523: 2829: 2797: 2791: 2785: 2779: 2747: 2562: 2556: 2523: 2517: 2484: 2452: 2446: 2440: 2407: 2375: 2369: 2363: 2357: 2325: 2292: 2286: 2280: 2248: 2215: 2177: 244:{\displaystyle \mathbb {R} \cup \{\infty \}} 238: 232: 27:Real numbers with an added point at infinity 6640:{\displaystyle {\overline {\mathbb {R} }}.} 6509:{\displaystyle {\overline {\mathbb {R} }}.} 2586:when dividing by an interval containing 0. 894:, the following operations are defined for 6932:{\displaystyle (a,b]^{\complement }=(b,a]} 6329:{\displaystyle {\widehat {\mathbb {R} }}.} 6267:{\displaystyle {\widehat {\mathbb {R} }}.} 6027:{\displaystyle {\widehat {\mathbb {R} }}.} 5676:{\displaystyle \lim _{x\to p}{f(x)}=f(p).} 4256:{\displaystyle \lim _{x\to p^{-}}{f(x)}=L} 4196:{\displaystyle \lim _{x\to p^{+}}{f(x)}=L} 3085: 3081: 2130:{\displaystyle a,b\in \mathbb {R} ,a<b} 307:{\displaystyle {\widehat {\mathbb {R} }}.} 7171: 7154: 7113: 7076: 7075: 7073: 7072: 7070: 7038: 7026:{\displaystyle {\widehat {\mathbb {R} }}} 7013: 7012: 7010: 7009: 7007: 6987: 6962: 6961: 6959: 6958: 6944: 6905: 6887: 6848: 6830: 6805:{\displaystyle {\widehat {\mathbb {R} }}} 6792: 6791: 6789: 6788: 6786: 6625: 6624: 6622: 6620: 6591: 6590: 6588: 6587: 6579: 6560: 6559: 6557: 6529: 6521: 6494: 6493: 6491: 6489: 6474:{\displaystyle {\widehat {\mathbb {R} }}} 6461: 6460: 6458: 6457: 6455: 6426: 6404: 6403: 6401: 6378: 6356: 6355: 6353: 6313: 6312: 6310: 6309: 6307: 6288: 6287: 6285: 6251: 6250: 6248: 6247: 6245: 6223: 6222: 6220: 6200: 6175: 6174: 6163: 6133: 6120: 6097: 6063: 6043: 6011: 6010: 6008: 6007: 6005: 5993:{\displaystyle {\widehat {\mathbb {R} }}} 5980: 5979: 5977: 5976: 5974: 5962:{\displaystyle {\widehat {\mathbb {R} }}} 5949: 5948: 5946: 5945: 5943: 5871: 5824: 5786: 5752: 5751: 5749: 5748: 5734: 5703: 5702: 5700: 5699: 5691: 5641: 5629: 5623: 5567: 5566: 5564: 5563: 5543: 5542: 5540: 5539: 5526: 5525: 5523: 5522: 5514: 5469: 5426: 5378: 5346: 5325:, if and only if for every neighbourhood 5273: 5272: 5270: 5269: 5250: 5249: 5247: 5246: 5227: 5226: 5224: 5223: 5204: 5203: 5201: 5200: 5187: 5186: 5184: 5183: 5175: 5144: 5118: 5077: 5076: 5074: 5073: 5065: 5027: 5010: 5009: 4994: 4988: 4953: 4945: 4934: 4928: 4897: 4880: 4879: 4864: 4858: 4823: 4815: 4804: 4798: 4767: 4750: 4749: 4737: 4731: 4696: 4684: 4678: 4642: 4627: 4621: 4586: 4578: 4567: 4561: 4525: 4510: 4504: 4469: 4461: 4450: 4444: 4408: 4396: 4390: 4355: 4343: 4337: 4312: 4311: 4297: 4275: 4274: 4272: 4233: 4225: 4214: 4208: 4173: 4165: 4154: 4148: 4113: 4101: 4095: 4055: 4029: 3967: 3959: 3948: 3918: 3910: 3899: 3893: 3828: 3802: 3748: 3736: 3730: 3673: 3672: 3670: 3669: 3661: 3633: 3632: 3630: 3629: 3621: 3594: 3593: 3591: 3590: 3577: 3576: 3574: 3573: 3565: 3515: 3486: 3440: 3410: 3364: 3334: 3262: 3261: 3259: 3258: 3250: 3225: 3224: 3222: 3221: 3213: 3193:{\displaystyle {\widehat {\mathbb {R} }}} 3180: 3179: 3177: 3176: 3174: 3117: 3104: 3086: 3058: 3030: 3029: 3027: 3026: 3012: 2993: 2992: 2990: 2978:{\displaystyle {\widehat {\mathbb {R} }}} 2965: 2964: 2962: 2961: 2959: 2927: 2926: 2924: 2881: 2862: 2861: 2847: 2813: 2812: 2763: 2762: 2727: 2708: 2707: 2705: 2689:{\displaystyle {\widehat {\mathbb {R} }}} 2676: 2675: 2673: 2672: 2670: 2647:{\displaystyle {\widehat {\mathbb {R} }}} 2634: 2633: 2631: 2630: 2628: 2612:{\displaystyle {\widehat {\mathbb {R} }}} 2599: 2598: 2596: 2595: 2593: 2468: 2467: 2391: 2390: 2341: 2340: 2264: 2263: 2193: 2192: 2147: 2145: 2111: 2110: 2096: 2084:{\displaystyle {\widehat {\mathbb {R} }}} 2071: 2070: 2068: 2067: 2065: 2041:{\displaystyle {\widehat {\mathbb {R} }}} 2028: 2027: 2025: 2024: 2022: 2003: 2002: 2000: 1952: 1951: 1887: 1884: 1883: 1858: 1787: 1785: 1755: 1754: 1752: 1751: 1731: 1699: 1515: 1513: 1483: 1482: 1480: 1479: 1459: 1435:{\displaystyle {\widehat {\mathbb {R} }}} 1422: 1421: 1419: 1418: 1416: 1395: 1389: 1356: 1340: 1276: 1274: 1211: 1148: 1109: 1046: 941: 939: 911: 910: 908: 907: 899: 887:{\displaystyle {\widehat {\mathbb {R} }}} 874: 873: 871: 870: 868: 849: 848: 846: 797: 793: 792: 789: 688:is the way the real projective line is a 665:{\displaystyle {\widehat {\mathbb {R} }}} 652: 651: 649: 648: 646: 627: 626: 624: 612:{\displaystyle {\widehat {\mathbb {R} }}} 599: 598: 596: 595: 593: 556:{\displaystyle {\widehat {\mathbb {R} }}} 543: 542: 540: 539: 537: 395: 393: 291: 290: 288: 287: 285: 264: 260: 259: 256: 225: 224: 222: 199: 198: 196: 135:Learn how and when to remove this message 6545:{\displaystyle x\mapsto {\frac {1}{x}}.} 5492:{\displaystyle A\cup \lbrace p\rbrace .} 5449:{\displaystyle A\cup \lbrace p\rbrace ,} 762:of linear fractional transformations is 512:of the real line) distinguishes between 7222: 7086: 6989: 6774: 4008:if and only if for every neighbourhood 3781:if and only if for every neighbourhood 6336:This is the case, for example, of the 5109:if and only if every neighbourhood of 4431:{\displaystyle \lim _{x\to p}{f(x)}=L} 4378:{\displaystyle \lim _{x\to p}{f(x)}=L} 4136:{\displaystyle \lim _{x\to p}{f(x)}=L} 3771:{\displaystyle \lim _{x\to p}{f(x)}=L} 834:Arithmetic operations that are defined 414:{\displaystyle {\frac {a}{0}}=\infty } 6875:{\displaystyle ^{\complement }=(b,a)} 6812:, resolve to the standard rules: see 5333:, there is a punctured neighbourhood 3789:, there is a punctured neighbourhood 7: 7269:"Projectively Extended Real Numbers" 7262: 7260: 7258: 7256: 7254: 7252: 7234: 7232: 7230: 7228: 7226: 7149:For example, the ratio of intervals 6669:is considered in the context of the 6483:affinely extended real number system 6373:but it cannot be made continuous at 5415:topological definition of continuity 4322:{\displaystyle p,L\in \mathbb {R} ,} 3169:can be used to analyze functions of 822:Motivation for arithmetic operations 563:in a meaningful way. Given a number 73:adding citations to reliable sources 6712:. Collectively they form the group 6034:In particular, this is the case of 2869:{\displaystyle a,b\in \mathbb {R} } 6581: 6428: 6380: 6160: 6065: 6045: 5039: 5004: 4970: 4942: 4909: 4874: 4840: 4812: 4779: 4713: 4637: 4575: 4520: 4458: 3321:is a right-sided neighbourhood of 2788: 2559: 2541: 2535: 2443: 2419: 2366: 2289: 2233: 1689: 1345: 1337: 1329: 1309: 1301: 1295: 1287: 1281: 1187: 1171: 1165: 1138: 1124: 1106: 1099: 1051: 1036: 1022: 1006: 1000: 987: 973: 957: 951: 506:affinely extended real number line 408: 363:affinely extended real number line 235: 25: 6516:This is the case of the function 3397:is a left-sided neighbourhood of 84:"Projectively extended real line" 6704:, since the real numbers form a 5413:This corresponds to the regular 3435:contains the semi-open interval 3359:contains the semi-open interval 2696:. Sufficient for a base are the 931:, with exceptions as indicated: 806:{\displaystyle \mathbb {R} ^{2}} 273:{\displaystyle \mathbb {R} ^{*}} 49: 5556: 3938: 1450:The following equalities mean: 532:relation cannot be extended to 173:projectively extended real line 60:needs additional citations for 7188: 7176: 7168: 7156: 7127: 7115: 7052: 7040: 6926: 6914: 6902: 6889: 6869: 6857: 6845: 6832: 6526: 5882: 5876: 5835: 5829: 5745: 5667: 5661: 5651: 5645: 5633: 5536: 5389: 5383: 5197: 5028: 5024: 5018: 5011: 4998: 4963: 4957: 4938: 4898: 4894: 4888: 4881: 4868: 4833: 4827: 4808: 4768: 4764: 4758: 4751: 4741: 4706: 4700: 4688: 4652: 4646: 4631: 4596: 4590: 4571: 4535: 4529: 4514: 4479: 4473: 4454: 4418: 4412: 4400: 4365: 4359: 4347: 4243: 4237: 4218: 4183: 4177: 4158: 4123: 4117: 4105: 4066: 4060: 3977: 3971: 3952: 3928: 3922: 3903: 3839: 3833: 3758: 3752: 3740: 3587: 3454: 3442: 3378: 3366: 3082: 3078: 3066: 2741: 2729: 1969: 1957: 1937: 1925: 1902: 1890: 1809: 1797: 1647: 1635: 1613: 1601: 1565: 1553: 1531: 1519: 830:of functions of real numbers. 314:The added point is called the 1: 7205:in both intervals, and since 6679:projective harmonic conjugate 6414:{\displaystyle \mathbb {R} ,} 6366:{\displaystyle \mathbb {R} ,} 6233:{\displaystyle \mathbb {R} ,} 5056:Extended definition of limits 2937:{\displaystyle \mathbb {R} .} 696:to a circle. For example the 680:Fundamental to the idea that 7292:Lee, Nam-Hoon (2020-04-28). 6995:{\displaystyle \varnothing } 6629: 6567:{\displaystyle \mathbb {R} } 6498: 6295:{\displaystyle \mathbb {R} } 5366:{\displaystyle x\in A\cap C} 4282:{\displaystyle \mathbb {R} } 3503:{\displaystyle x\not \in A,} 3401:, if there is a real number 3325:, if there is a real number 3000:{\displaystyle \mathbb {R} } 2715:{\displaystyle \mathbb {R} } 2654:excluding any single point. 2010:{\displaystyle \mathbb {R} } 856:{\displaystyle \mathbb {R} } 634:{\displaystyle \mathbb {R} } 206:{\displaystyle \mathbb {R} } 6710:projective line over a ring 6673:, then the consequences of 3556:Basic definitions of limits 3535:{\displaystyle A\cup \{x\}} 686:no different from any other 508:(also called the two-point 477:Extensions of the real line 183:), is the extension of the 7357: 6658: 6348:function is continuous in 5781:if and only if, for every 5404:{\displaystyle f(x)\in B.} 4267:Comparison with limits in 4081:{\displaystyle f(x)\in A.} 3305:contains an open interval 2623:are also intervals, as is 700:of 2 Γ— 2 real 641:is used in definitions in 177:one-point compactification 29: 6647:This is the case for the 6611:become continuous if the 3881:from the right (left) is 3851:{\displaystyle f(x)\in A} 2907:As said, the topology is 489:in the same way that the 40:Extended real number line 6758:Complex projective plane 6437:{\displaystyle \infty .} 6389:{\displaystyle \infty .} 6074:{\displaystyle \infty ,} 5161:{\displaystyle y\neq p.} 2911:to a circle. Thus it is 2657:The open intervals as a 157:stereographic projection 7239:NBU, DDE (2019-11-05). 6342:trigonometric functions 6280:that are continuous in 6051:{\displaystyle \infty } 6038:, which take the value 3475:punctured neighbourhood 3424:{\displaystyle y\neq x} 3348:{\displaystyle y\neq x} 2898:{\displaystyle a<b.} 7195: 7140:, remaining undefined. 7134: 7102: 7059: 7027: 6996: 6976: 6933: 6876: 6806: 6641: 6605: 6568: 6546: 6510: 6475: 6438: 6415: 6390: 6367: 6330: 6296: 6268: 6234: 6209: 6186: 6106: 6075: 6052: 6028: 6000:that is continuous in 5994: 5963: 5892: 5842: 5801: 5800:{\displaystyle p\in A} 5766: 5720: 5677: 5584: 5493: 5450: 5405: 5367: 5287: 5162: 5133: 5132:{\displaystyle y\in A} 5091: 5046: 4977: 4916: 4847: 4786: 4720: 4666: 4610: 4549: 4493: 4432: 4379: 4323: 4283: 4257: 4197: 4137: 4082: 4044: 4043:{\displaystyle x\in B} 3999: 3852: 3817: 3816:{\displaystyle x\in B} 3772: 3687: 3650: 3611: 3536: 3504: 3461: 3425: 3385: 3349: 3276: 3239: 3194: 3140: 3044: 3001: 2979: 2938: 2899: 2870: 2836: 2716: 2690: 2648: 2613: 2573: 2131: 2085: 2052:Intervals and topology 2042: 2011: 1986: 1772: 1717: 1500: 1436: 1411:cannot be extended to 1405: 1372: 1251: 925: 888: 857: 807: 717:MΓΆbius transformations 666: 635: 613: 557: 469:of a vertical line is 415: 330:of real numbers whose 308: 274: 245: 207: 164: 7273:mathworld.wolfram.com 7196: 7135: 7133:{\displaystyle (a,a]} 7103: 7065:being interpreted as 7060: 7058:{\displaystyle (a,a)} 7028: 6997: 6977: 6934: 6877: 6807: 6753:Real projective plane 6729:hyperbolic involution 6671:real projective plane 6655:As a projective range 6642: 6606: 6574:and discontinuous at 6569: 6547: 6511: 6476: 6439: 6416: 6391: 6368: 6331: 6297: 6269: 6235: 6210: 6208:{\displaystyle \tan } 6187: 6107: 6105:{\displaystyle \tan } 6076: 6053: 6029: 5995: 5964: 5893: 5891:{\displaystyle f(p).} 5843: 5802: 5767: 5721: 5678: 5585: 5494: 5451: 5406: 5368: 5288: 5163: 5134: 5092: 5047: 4978: 4917: 4848: 4787: 4721: 4667: 4611: 4550: 4494: 4433: 4380: 4324: 4284: 4258: 4198: 4138: 4090:It can be shown that 4083: 4045: 4000: 3853: 3818: 3773: 3688: 3651: 3612: 3537: 3505: 3462: 3460:{\displaystyle (y,x]} 3426: 3386: 3384:{\displaystyle [x,y)} 3350: 3277: 3240: 3195: 3141: 3045: 3002: 2980: 2939: 2900: 2871: 2837: 2717: 2691: 2649: 2614: 2574: 2132: 2086: 2043: 2012: 1987: 1773: 1718: 1501: 1454:This is true for any 1437: 1406: 1404:{\displaystyle e^{x}} 1373: 1252: 926: 889: 858: 817:Arithmetic operations 808: 667: 636: 614: 558: 493:extends the field of 416: 309: 275: 246: 217:. It is thus the set 213:, by a point denoted 208: 159:) with an additional 150: 7153: 7112: 7069: 7037: 7006: 6986: 6943: 6886: 6829: 6785: 6667:real projective line 6619: 6578: 6556: 6520: 6488: 6454: 6425: 6400: 6377: 6352: 6338:exponential function 6306: 6284: 6278:elementary functions 6244: 6219: 6199: 6119: 6112:is extended so that 6096: 6062: 6042: 6036:polynomial functions 6004: 5973: 5942: 5870: 5841:{\displaystyle f(x)} 5823: 5785: 5733: 5690: 5622: 5513: 5468: 5425: 5377: 5345: 5174: 5143: 5117: 5064: 4987: 4927: 4857: 4797: 4730: 4677: 4620: 4560: 4503: 4443: 4389: 4336: 4296: 4271: 4207: 4147: 4143:if and only if both 4094: 4054: 4028: 3892: 3827: 3801: 3729: 3660: 3620: 3564: 3514: 3485: 3439: 3409: 3363: 3333: 3249: 3212: 3173: 3057: 3011: 2989: 2958: 2923: 2880: 2846: 2726: 2704: 2669: 2627: 2592: 2144: 2095: 2064: 2021: 1999: 1784: 1730: 1512: 1458: 1446:Algebraic properties 1415: 1388: 1383:exponential function 1273: 938: 898: 867: 845: 788: 715:may be expressed by 698:general linear group 645: 623: 619:. However, order on 592: 536: 392: 347:real projective line 284: 255: 221: 195: 69:improve this article 7336:Projective geometry 7298:. Springer Nature. 7267:Weisstein, Eric W. 6344:. For example, the 2952:Interval arithmetic 2947:Interval arithmetic 2584:interval arithmetic 2060:can be extended to 2017:are also valid for 7331:Topological spaces 7191: 7130: 7098: 7055: 7023: 6992: 6972: 6929: 6872: 6802: 6675:Desargues' theorem 6637: 6601: 6564: 6542: 6506: 6471: 6434: 6411: 6386: 6363: 6326: 6292: 6264: 6230: 6205: 6182: 6102: 6071: 6048: 6024: 5990: 5959: 5888: 5838: 5797: 5762: 5716: 5673: 5640: 5580: 5489: 5446: 5401: 5363: 5283: 5158: 5129: 5087: 5042: 5008: 4973: 4952: 4912: 4878: 4843: 4822: 4782: 4748: 4716: 4695: 4662: 4641: 4606: 4585: 4545: 4524: 4489: 4468: 4428: 4407: 4375: 4354: 4319: 4279: 4253: 4232: 4193: 4172: 4133: 4112: 4078: 4040: 3995: 3966: 3917: 3848: 3813: 3768: 3747: 3683: 3646: 3607: 3532: 3500: 3457: 3421: 3381: 3345: 3272: 3235: 3190: 3136: 3040: 2997: 2975: 2934: 2895: 2866: 2832: 2722:and the intervals 2712: 2700:open intervals in 2686: 2644: 2609: 2569: 2567: 2127: 2081: 2056:The concept of an 2038: 2007: 1982: 1980: 1768: 1713: 1711: 1496: 1432: 1401: 1368: 1366: 1247: 1245: 921: 884: 853: 803: 662: 631: 609: 553: 457:, and none of the 411: 304: 270: 241: 203: 165: 7305:978-3-030-42101-4 7194:{\displaystyle /} 7083: 7020: 6969: 6799: 6683:point at infinity 6632: 6598: 6537: 6501: 6468: 6320: 6258: 6215:is continuous in 6166: 6141: 6018: 5987: 5956: 5902:rational function 5819:and the limit of 5775:is continuous in 5759: 5710: 5625: 5574: 5550: 5533: 5419:subspace topology 5417:, applied to the 5297:a limit point of 5280: 5257: 5234: 5211: 5194: 5113:includes a point 5084: 4990: 4983:is equivalent to 4930: 4860: 4853:is equivalent to 4800: 4733: 4726:is equivalent to 4680: 4623: 4616:is equivalent to 4563: 4506: 4499:is equivalent to 4446: 4392: 4385:is equivalent to 4339: 4210: 4150: 4097: 3944: 3895: 3732: 3680: 3640: 3601: 3584: 3269: 3232: 3187: 3125: 3112: 3094: 3037: 2972: 2683: 2641: 2606: 2078: 2035: 1909: 1866: 1762: 1707: 1490: 1429: 918: 881: 764:triply transitive 709:transitive action 690:homogeneous space 659: 606: 550: 504:In contrast, the 428:. In particular, 403: 316:point at infinity 298: 175:(also called the 161:point at infinity 155:(by some form of 145: 144: 137: 119: 16:(Redirected from 7348: 7310: 7309: 7289: 7283: 7282: 7280: 7279: 7264: 7247: 7246: 7236: 7210: 7208: 7204: 7200: 7198: 7197: 7192: 7175: 7147: 7141: 7139: 7137: 7136: 7131: 7107: 7105: 7104: 7099: 7085: 7084: 7079: 7074: 7064: 7062: 7061: 7056: 7032: 7030: 7029: 7024: 7022: 7021: 7016: 7011: 7001: 6999: 6998: 6993: 6981: 6979: 6978: 6973: 6971: 6970: 6965: 6960: 6938: 6936: 6935: 6930: 6910: 6909: 6881: 6879: 6878: 6873: 6853: 6852: 6823: 6817: 6811: 6809: 6808: 6803: 6801: 6800: 6795: 6790: 6779: 6661:Projective range 6646: 6644: 6643: 6638: 6633: 6628: 6623: 6610: 6608: 6607: 6602: 6600: 6599: 6594: 6589: 6573: 6571: 6570: 6565: 6563: 6551: 6549: 6548: 6543: 6538: 6530: 6515: 6513: 6512: 6507: 6502: 6497: 6492: 6480: 6478: 6477: 6472: 6470: 6469: 6464: 6459: 6443: 6441: 6440: 6435: 6420: 6418: 6417: 6412: 6407: 6395: 6393: 6392: 6387: 6372: 6370: 6369: 6364: 6359: 6335: 6333: 6332: 6327: 6322: 6321: 6316: 6311: 6301: 6299: 6298: 6293: 6291: 6273: 6271: 6270: 6265: 6260: 6259: 6254: 6249: 6239: 6237: 6236: 6231: 6226: 6214: 6212: 6211: 6206: 6191: 6189: 6188: 6183: 6178: 6167: 6164: 6156: 6152: 6142: 6134: 6111: 6109: 6108: 6103: 6081:if they are not 6080: 6078: 6077: 6072: 6057: 6055: 6054: 6049: 6033: 6031: 6030: 6025: 6020: 6019: 6014: 6009: 5999: 5997: 5996: 5991: 5989: 5988: 5983: 5978: 5968: 5966: 5965: 5960: 5958: 5957: 5952: 5947: 5933: 5927: 5921: 5897: 5895: 5894: 5889: 5865: 5859: 5853: 5847: 5845: 5844: 5839: 5818: 5812: 5806: 5804: 5803: 5798: 5780: 5771: 5769: 5768: 5763: 5761: 5760: 5755: 5750: 5725: 5723: 5722: 5717: 5712: 5711: 5706: 5701: 5682: 5680: 5679: 5674: 5654: 5639: 5614: 5608: 5602: 5589: 5587: 5586: 5581: 5576: 5575: 5570: 5565: 5552: 5551: 5546: 5541: 5535: 5534: 5529: 5524: 5498: 5496: 5495: 5490: 5455: 5453: 5452: 5447: 5410: 5408: 5407: 5402: 5372: 5370: 5369: 5364: 5292: 5290: 5289: 5284: 5282: 5281: 5276: 5271: 5259: 5258: 5253: 5248: 5236: 5235: 5230: 5225: 5213: 5212: 5207: 5202: 5196: 5195: 5190: 5185: 5167: 5165: 5164: 5159: 5138: 5136: 5135: 5130: 5096: 5094: 5093: 5088: 5086: 5085: 5080: 5075: 5051: 5049: 5048: 5043: 5032: 5031: 5014: 5007: 4982: 4980: 4979: 4974: 4966: 4951: 4950: 4949: 4921: 4919: 4918: 4913: 4902: 4901: 4884: 4877: 4852: 4850: 4849: 4844: 4836: 4821: 4820: 4819: 4791: 4789: 4788: 4783: 4772: 4771: 4754: 4747: 4725: 4723: 4722: 4717: 4709: 4694: 4671: 4669: 4668: 4663: 4655: 4640: 4615: 4613: 4612: 4607: 4599: 4584: 4583: 4582: 4554: 4552: 4551: 4546: 4538: 4523: 4498: 4496: 4495: 4490: 4482: 4467: 4466: 4465: 4437: 4435: 4434: 4429: 4421: 4406: 4384: 4382: 4381: 4376: 4368: 4353: 4328: 4326: 4325: 4320: 4315: 4288: 4286: 4285: 4280: 4278: 4262: 4260: 4259: 4254: 4246: 4231: 4230: 4229: 4202: 4200: 4199: 4194: 4186: 4171: 4170: 4169: 4142: 4140: 4139: 4134: 4126: 4111: 4087: 4085: 4084: 4079: 4049: 4047: 4046: 4041: 4004: 4002: 4001: 3996: 3991: 3987: 3980: 3965: 3964: 3963: 3931: 3916: 3915: 3914: 3857: 3855: 3854: 3849: 3822: 3820: 3819: 3814: 3777: 3775: 3774: 3769: 3761: 3746: 3713: 3692: 3690: 3689: 3684: 3682: 3681: 3676: 3671: 3655: 3653: 3652: 3647: 3642: 3641: 3636: 3631: 3616: 3614: 3613: 3608: 3603: 3602: 3597: 3592: 3586: 3585: 3580: 3575: 3545: 3541: 3539: 3538: 3533: 3509: 3507: 3506: 3501: 3480: 3472: 3466: 3464: 3463: 3458: 3434: 3430: 3428: 3427: 3422: 3404: 3400: 3396: 3390: 3388: 3387: 3382: 3358: 3354: 3352: 3351: 3346: 3328: 3324: 3320: 3314: 3310: 3304: 3298: 3288: 3281: 3279: 3278: 3273: 3271: 3270: 3265: 3260: 3244: 3242: 3241: 3236: 3234: 3233: 3228: 3223: 3199: 3197: 3196: 3191: 3189: 3188: 3183: 3178: 3156: 3152: 3145: 3143: 3142: 3137: 3131: 3127: 3126: 3118: 3113: 3105: 3095: 3087: 3049: 3047: 3046: 3041: 3039: 3038: 3033: 3028: 3006: 3004: 3003: 2998: 2996: 2984: 2982: 2981: 2976: 2974: 2973: 2968: 2963: 2943: 2941: 2940: 2935: 2930: 2904: 2902: 2901: 2896: 2875: 2873: 2872: 2867: 2865: 2841: 2839: 2838: 2833: 2816: 2766: 2721: 2719: 2718: 2713: 2711: 2695: 2693: 2692: 2687: 2685: 2684: 2679: 2674: 2653: 2651: 2650: 2645: 2643: 2642: 2637: 2632: 2618: 2616: 2615: 2610: 2608: 2607: 2602: 2597: 2578: 2576: 2575: 2570: 2568: 2548: 2544: 2509: 2505: 2471: 2432: 2428: 2394: 2344: 2317: 2313: 2267: 2240: 2236: 2196: 2169: 2165: 2136: 2134: 2133: 2128: 2114: 2090: 2088: 2087: 2082: 2080: 2079: 2074: 2069: 2047: 2045: 2044: 2039: 2037: 2036: 2031: 2026: 2016: 2014: 2013: 2008: 2006: 1991: 1989: 1988: 1983: 1981: 1910: 1905: 1888: 1871: 1867: 1859: 1777: 1775: 1774: 1769: 1764: 1763: 1758: 1753: 1722: 1720: 1719: 1714: 1712: 1708: 1700: 1505: 1503: 1502: 1497: 1492: 1491: 1486: 1481: 1441: 1439: 1438: 1433: 1431: 1430: 1425: 1420: 1410: 1408: 1407: 1402: 1400: 1399: 1377: 1375: 1374: 1369: 1367: 1360: 1351: 1344: 1335: 1321: 1307: 1293: 1279: 1256: 1254: 1253: 1248: 1246: 1215: 1152: 1113: 1050: 930: 928: 927: 922: 920: 919: 914: 909: 893: 891: 890: 885: 883: 882: 877: 872: 862: 860: 859: 854: 852: 812: 810: 809: 804: 802: 801: 796: 782:linear subspaces 773:The terminology 757: 726: 722: 683: 671: 669: 668: 663: 661: 660: 655: 650: 640: 638: 637: 632: 630: 618: 616: 615: 610: 608: 607: 602: 597: 587: 583: 576: 569: 562: 560: 559: 554: 552: 551: 546: 541: 519: 515: 510:compactification 500: 472: 464: 448: 435: 431: 420: 418: 417: 412: 404: 396: 383:division by zero 377:Dividing by zero 372: 368: 360: 356: 352: 313: 311: 310: 305: 300: 299: 294: 289: 279: 277: 276: 271: 269: 268: 263: 250: 248: 247: 242: 228: 216: 212: 210: 209: 204: 202: 140: 133: 129: 126: 120: 118: 77: 53: 45: 37: 33: 21: 7356: 7355: 7351: 7350: 7349: 7347: 7346: 7345: 7316: 7315: 7314: 7313: 7306: 7291: 7290: 7286: 7277: 7275: 7266: 7265: 7250: 7238: 7237: 7224: 7219: 7214: 7213: 7206: 7202: 7151: 7150: 7148: 7144: 7110: 7109: 7067: 7066: 7035: 7034: 7004: 7003: 6984: 6983: 6941: 6940: 6901: 6884: 6883: 6844: 6827: 6826: 6824: 6820: 6783: 6782: 6780: 6776: 6771: 6749: 6663: 6657: 6617: 6616: 6615:is extended to 6576: 6575: 6554: 6553: 6518: 6517: 6486: 6485: 6452: 6451: 6450:is extended to 6423: 6422: 6398: 6397: 6375: 6374: 6350: 6349: 6304: 6303: 6282: 6281: 6242: 6241: 6217: 6216: 6197: 6196: 6165: for  6132: 6128: 6117: 6116: 6094: 6093: 6060: 6059: 6040: 6039: 6002: 6001: 5971: 5970: 5940: 5939: 5929: 5923: 5904: 5868: 5867: 5861: 5855: 5849: 5821: 5820: 5814: 5808: 5783: 5782: 5776: 5731: 5730: 5688: 5687: 5620: 5619: 5610: 5604: 5603:if and only if 5598: 5511: 5510: 5504: 5466: 5465: 5423: 5422: 5375: 5374: 5343: 5342: 5301:. The limit of 5172: 5171: 5141: 5140: 5115: 5114: 5062: 5061: 5058: 4985: 4984: 4941: 4925: 4924: 4855: 4854: 4811: 4795: 4794: 4728: 4727: 4675: 4674: 4618: 4617: 4574: 4558: 4557: 4501: 4500: 4457: 4441: 4440: 4387: 4386: 4334: 4333: 4294: 4293: 4290: 4269: 4268: 4221: 4205: 4204: 4161: 4145: 4144: 4092: 4091: 4052: 4051: 4026: 4025: 3955: 3943: 3939: 3906: 3890: 3889: 3863:one-sided limit 3825: 3824: 3799: 3798: 3727: 3726: 3709: 3658: 3657: 3618: 3617: 3562: 3561: 3558: 3553: 3543: 3512: 3511: 3483: 3482: 3478: 3470: 3437: 3436: 3432: 3407: 3406: 3402: 3398: 3394: 3361: 3360: 3356: 3331: 3330: 3326: 3322: 3318: 3312: 3306: 3300: 3294: 3286: 3247: 3246: 3210: 3209: 3206: 3171: 3170: 3163: 3154: 3150: 3103: 3099: 3055: 3054: 3009: 3008: 2987: 2986: 2956: 2955: 2949: 2921: 2920: 2878: 2877: 2844: 2843: 2724: 2723: 2702: 2701: 2667: 2666: 2625: 2624: 2590: 2589: 2566: 2565: 2549: 2534: 2530: 2527: 2526: 2510: 2495: 2491: 2488: 2487: 2433: 2418: 2414: 2411: 2410: 2318: 2303: 2299: 2296: 2295: 2241: 2226: 2222: 2219: 2218: 2170: 2155: 2151: 2142: 2141: 2093: 2092: 2062: 2061: 2054: 2019: 2018: 1997: 1996: 1979: 1978: 1953: 1946: 1918: 1912: 1911: 1889: 1885: 1878: 1854: 1847: 1841: 1840: 1812: 1782: 1781: 1728: 1727: 1710: 1709: 1692: 1680: 1679: 1663: 1651: 1650: 1622: 1598: 1597: 1581: 1569: 1568: 1540: 1510: 1509: 1456: 1455: 1448: 1413: 1412: 1391: 1386: 1385: 1365: 1364: 1349: 1348: 1333: 1332: 1319: 1318: 1305: 1304: 1291: 1290: 1271: 1270: 1263: 1244: 1243: 1232: 1219: 1205: 1204: 1193: 1180: 1142: 1141: 1130: 1117: 1103: 1102: 1091: 1078: 1040: 1039: 1028: 1015: 991: 990: 979: 966: 936: 935: 896: 895: 865: 864: 843: 842: 836: 824: 819: 791: 786: 785: 775:projective line 755: 724: 723:, the image is 720: 681: 678: 643: 642: 621: 620: 590: 589: 585: 578: 571: 564: 534: 533: 526: 517: 513: 498: 495:complex numbers 479: 470: 462: 443: 433: 429: 390: 389: 379: 370: 366: 358: 354: 350: 332:absolute values 282: 281: 258: 253: 252: 219: 218: 214: 193: 192: 141: 130: 124: 121: 78: 76: 66: 54: 43: 35: 31: 28: 23: 22: 18:Projected reals 15: 12: 11: 5: 7354: 7352: 7344: 7343: 7338: 7333: 7328: 7318: 7317: 7312: 7311: 7304: 7284: 7248: 7221: 7220: 7218: 7215: 7212: 7211: 7190: 7187: 7184: 7181: 7178: 7174: 7170: 7167: 7164: 7161: 7158: 7142: 7129: 7126: 7123: 7120: 7117: 7097: 7094: 7091: 7088: 7082: 7078: 7054: 7051: 7048: 7045: 7042: 7019: 7015: 6991: 6968: 6964: 6957: 6954: 6951: 6948: 6928: 6925: 6922: 6919: 6916: 6913: 6908: 6904: 6900: 6897: 6894: 6891: 6871: 6868: 6865: 6862: 6859: 6856: 6851: 6847: 6843: 6840: 6837: 6834: 6818: 6798: 6794: 6773: 6772: 6770: 6767: 6766: 6765: 6760: 6755: 6748: 6745: 6694:projectivities 6659:Main article: 6656: 6653: 6636: 6631: 6627: 6597: 6593: 6586: 6583: 6562: 6541: 6536: 6533: 6528: 6525: 6505: 6500: 6496: 6467: 6463: 6433: 6430: 6410: 6406: 6385: 6382: 6362: 6358: 6325: 6319: 6315: 6290: 6263: 6257: 6253: 6229: 6225: 6204: 6193: 6192: 6181: 6177: 6173: 6170: 6162: 6159: 6155: 6151: 6148: 6145: 6140: 6137: 6131: 6127: 6124: 6101: 6070: 6067: 6047: 6023: 6017: 6013: 5986: 5982: 5955: 5951: 5887: 5884: 5881: 5878: 5875: 5837: 5834: 5831: 5828: 5813:is defined at 5796: 5793: 5790: 5773: 5772: 5758: 5754: 5747: 5744: 5741: 5738: 5715: 5709: 5705: 5698: 5695: 5684: 5683: 5672: 5669: 5666: 5663: 5660: 5657: 5653: 5650: 5647: 5644: 5638: 5635: 5632: 5628: 5609:is defined at 5591: 5590: 5579: 5573: 5569: 5562: 5559: 5555: 5549: 5545: 5538: 5532: 5528: 5521: 5518: 5503: 5500: 5488: 5485: 5482: 5479: 5476: 5473: 5445: 5442: 5439: 5436: 5433: 5430: 5400: 5397: 5394: 5391: 5388: 5385: 5382: 5362: 5359: 5356: 5353: 5350: 5279: 5275: 5268: 5265: 5262: 5256: 5252: 5245: 5242: 5239: 5233: 5229: 5222: 5219: 5216: 5210: 5206: 5199: 5193: 5189: 5182: 5179: 5157: 5154: 5151: 5148: 5128: 5125: 5122: 5083: 5079: 5072: 5069: 5057: 5054: 5053: 5052: 5041: 5038: 5035: 5030: 5026: 5023: 5020: 5017: 5013: 5006: 5003: 5000: 4997: 4993: 4972: 4969: 4965: 4962: 4959: 4956: 4948: 4944: 4940: 4937: 4933: 4922: 4911: 4908: 4905: 4900: 4896: 4893: 4890: 4887: 4883: 4876: 4873: 4870: 4867: 4863: 4842: 4839: 4835: 4832: 4829: 4826: 4818: 4814: 4810: 4807: 4803: 4792: 4781: 4778: 4775: 4770: 4766: 4763: 4760: 4757: 4753: 4746: 4743: 4740: 4736: 4715: 4712: 4708: 4705: 4702: 4699: 4693: 4690: 4687: 4683: 4672: 4661: 4658: 4654: 4651: 4648: 4645: 4639: 4636: 4633: 4630: 4626: 4605: 4602: 4598: 4595: 4592: 4589: 4581: 4577: 4573: 4570: 4566: 4555: 4544: 4541: 4537: 4534: 4531: 4528: 4522: 4519: 4516: 4513: 4509: 4488: 4485: 4481: 4478: 4475: 4472: 4464: 4460: 4456: 4453: 4449: 4438: 4427: 4424: 4420: 4417: 4414: 4411: 4405: 4402: 4399: 4395: 4374: 4371: 4367: 4364: 4361: 4358: 4352: 4349: 4346: 4342: 4318: 4314: 4310: 4307: 4304: 4301: 4289: 4277: 4265: 4252: 4249: 4245: 4242: 4239: 4236: 4228: 4224: 4220: 4217: 4213: 4192: 4189: 4185: 4182: 4179: 4176: 4168: 4164: 4160: 4157: 4153: 4132: 4129: 4125: 4122: 4119: 4116: 4110: 4107: 4104: 4100: 4077: 4074: 4071: 4068: 4065: 4062: 4059: 4039: 4036: 4033: 4006: 4005: 3994: 3990: 3986: 3983: 3979: 3976: 3973: 3970: 3962: 3958: 3954: 3951: 3947: 3942: 3937: 3934: 3930: 3927: 3924: 3921: 3913: 3909: 3905: 3902: 3898: 3847: 3844: 3841: 3838: 3835: 3832: 3812: 3809: 3806: 3779: 3778: 3767: 3764: 3760: 3757: 3754: 3751: 3745: 3742: 3739: 3735: 3679: 3675: 3668: 3665: 3645: 3639: 3635: 3628: 3625: 3606: 3600: 3596: 3589: 3583: 3579: 3572: 3569: 3557: 3554: 3552: 3549: 3548: 3547: 3531: 3528: 3525: 3522: 3519: 3499: 3496: 3493: 3490: 3468: 3456: 3453: 3450: 3447: 3444: 3420: 3417: 3414: 3392: 3380: 3377: 3374: 3371: 3368: 3344: 3341: 3338: 3316: 3311:that contains 3268: 3264: 3257: 3254: 3231: 3227: 3220: 3217: 3205: 3204:Neighbourhoods 3202: 3186: 3182: 3162: 3159: 3147: 3146: 3135: 3130: 3124: 3121: 3116: 3111: 3108: 3102: 3098: 3093: 3090: 3084: 3080: 3077: 3074: 3071: 3068: 3065: 3062: 3036: 3032: 3025: 3022: 3019: 3016: 2995: 2971: 2967: 2948: 2945: 2933: 2929: 2894: 2891: 2888: 2885: 2864: 2860: 2857: 2854: 2851: 2831: 2828: 2825: 2822: 2819: 2815: 2811: 2808: 2805: 2802: 2799: 2796: 2793: 2790: 2787: 2784: 2781: 2778: 2775: 2772: 2769: 2765: 2761: 2758: 2755: 2752: 2749: 2746: 2743: 2740: 2737: 2734: 2731: 2710: 2682: 2678: 2640: 2636: 2605: 2601: 2580: 2579: 2564: 2561: 2558: 2555: 2552: 2550: 2547: 2543: 2540: 2537: 2533: 2529: 2528: 2525: 2522: 2519: 2516: 2513: 2511: 2508: 2504: 2501: 2498: 2494: 2490: 2489: 2486: 2483: 2480: 2477: 2474: 2470: 2466: 2463: 2460: 2457: 2454: 2451: 2448: 2445: 2442: 2439: 2436: 2434: 2431: 2427: 2424: 2421: 2417: 2413: 2412: 2409: 2406: 2403: 2400: 2397: 2393: 2389: 2386: 2383: 2380: 2377: 2374: 2371: 2368: 2365: 2362: 2359: 2356: 2353: 2350: 2347: 2343: 2339: 2336: 2333: 2330: 2327: 2324: 2321: 2319: 2316: 2312: 2309: 2306: 2302: 2298: 2297: 2294: 2291: 2288: 2285: 2282: 2279: 2276: 2273: 2270: 2266: 2262: 2259: 2256: 2253: 2250: 2247: 2244: 2242: 2239: 2235: 2232: 2229: 2225: 2221: 2220: 2217: 2214: 2211: 2208: 2205: 2202: 2199: 2195: 2191: 2188: 2185: 2182: 2179: 2176: 2173: 2171: 2168: 2164: 2161: 2158: 2154: 2150: 2149: 2126: 2123: 2120: 2117: 2113: 2109: 2106: 2103: 2100: 2077: 2073: 2053: 2050: 2034: 2030: 2005: 1993: 1992: 1977: 1974: 1971: 1968: 1965: 1962: 1959: 1956: 1954: 1950: 1947: 1945: 1942: 1939: 1936: 1933: 1930: 1927: 1924: 1921: 1919: 1917: 1914: 1913: 1908: 1904: 1901: 1898: 1895: 1892: 1886: 1882: 1879: 1877: 1874: 1870: 1865: 1862: 1857: 1853: 1850: 1848: 1846: 1843: 1842: 1839: 1836: 1833: 1830: 1827: 1824: 1821: 1818: 1815: 1813: 1811: 1808: 1805: 1802: 1799: 1796: 1793: 1790: 1789: 1767: 1761: 1757: 1750: 1747: 1744: 1741: 1738: 1735: 1724: 1723: 1706: 1703: 1698: 1695: 1693: 1691: 1688: 1685: 1682: 1681: 1678: 1675: 1672: 1669: 1666: 1664: 1662: 1659: 1656: 1653: 1652: 1649: 1646: 1643: 1640: 1637: 1634: 1631: 1628: 1625: 1623: 1621: 1618: 1615: 1612: 1609: 1606: 1603: 1600: 1599: 1596: 1593: 1590: 1587: 1584: 1582: 1580: 1577: 1574: 1571: 1570: 1567: 1564: 1561: 1558: 1555: 1552: 1549: 1546: 1543: 1541: 1539: 1536: 1533: 1530: 1527: 1524: 1521: 1518: 1517: 1495: 1489: 1485: 1478: 1475: 1472: 1469: 1466: 1463: 1447: 1444: 1428: 1424: 1398: 1394: 1379: 1378: 1363: 1359: 1355: 1352: 1350: 1347: 1343: 1339: 1336: 1334: 1331: 1328: 1325: 1322: 1320: 1317: 1314: 1311: 1308: 1306: 1303: 1300: 1297: 1294: 1292: 1289: 1286: 1283: 1280: 1278: 1262: 1259: 1258: 1257: 1242: 1239: 1236: 1233: 1231: 1228: 1225: 1222: 1220: 1218: 1214: 1210: 1207: 1206: 1203: 1200: 1197: 1194: 1192: 1189: 1186: 1183: 1181: 1179: 1176: 1173: 1170: 1167: 1164: 1161: 1158: 1155: 1151: 1147: 1144: 1143: 1140: 1137: 1134: 1131: 1129: 1126: 1123: 1120: 1118: 1116: 1112: 1108: 1105: 1104: 1101: 1098: 1095: 1092: 1090: 1087: 1084: 1081: 1079: 1077: 1074: 1071: 1068: 1065: 1062: 1059: 1056: 1053: 1049: 1045: 1042: 1041: 1038: 1035: 1032: 1029: 1027: 1024: 1021: 1018: 1016: 1014: 1011: 1008: 1005: 1002: 999: 996: 993: 992: 989: 986: 983: 980: 978: 975: 972: 969: 967: 965: 962: 959: 956: 953: 950: 947: 944: 943: 917: 913: 906: 903: 880: 876: 851: 835: 832: 823: 820: 818: 815: 800: 795: 770:is invariant. 677: 674: 658: 654: 629: 605: 601: 549: 545: 525: 522: 491:Riemann sphere 478: 475: 451:total function 422: 421: 410: 407: 402: 399: 378: 375: 373:are distinct. 303: 297: 293: 267: 262: 240: 237: 234: 231: 227: 201: 143: 142: 57: 55: 48: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 7353: 7342: 7339: 7337: 7334: 7332: 7329: 7327: 7326:Real analysis 7324: 7323: 7321: 7307: 7301: 7297: 7296: 7288: 7285: 7274: 7270: 7263: 7261: 7259: 7257: 7255: 7253: 7249: 7244: 7243: 7242:PG MTM 201 B1 7235: 7233: 7231: 7229: 7227: 7223: 7216: 7185: 7182: 7179: 7172: 7165: 7162: 7159: 7146: 7143: 7124: 7121: 7118: 7092: 7080: 7049: 7046: 7043: 7017: 6966: 6955: 6952: 6949: 6946: 6923: 6920: 6917: 6911: 6906: 6898: 6895: 6892: 6866: 6863: 6860: 6854: 6849: 6841: 6838: 6835: 6822: 6819: 6815: 6796: 6778: 6775: 6768: 6764: 6761: 6759: 6756: 6754: 6751: 6750: 6746: 6744: 6742: 6741:reciprocation 6738: 6734: 6730: 6726: 6721: 6719: 6717: 6711: 6707: 6703: 6699: 6698:automorphisms 6695: 6690: 6688: 6684: 6680: 6676: 6672: 6668: 6662: 6654: 6652: 6650: 6634: 6614: 6595: 6584: 6539: 6534: 6531: 6523: 6503: 6484: 6465: 6449: 6444: 6431: 6408: 6383: 6360: 6347: 6343: 6339: 6323: 6317: 6279: 6274: 6261: 6255: 6227: 6202: 6179: 6171: 6168: 6157: 6153: 6149: 6146: 6143: 6138: 6135: 6129: 6125: 6122: 6115: 6114: 6113: 6099: 6091: 6088:Also, if the 6086: 6084: 6068: 6037: 6021: 6015: 5984: 5953: 5937: 5932: 5926: 5919: 5915: 5911: 5907: 5903: 5898: 5885: 5879: 5873: 5864: 5858: 5852: 5832: 5826: 5817: 5811: 5794: 5791: 5788: 5779: 5756: 5742: 5739: 5736: 5729: 5728: 5727: 5726:the function 5713: 5707: 5696: 5693: 5670: 5664: 5658: 5655: 5648: 5642: 5636: 5630: 5618: 5617: 5616: 5613: 5607: 5601: 5596: 5577: 5571: 5560: 5557: 5553: 5547: 5530: 5519: 5516: 5509: 5508: 5507: 5506:The function 5501: 5499: 5486: 5480: 5474: 5471: 5463: 5459: 5443: 5437: 5431: 5428: 5420: 5416: 5411: 5398: 5395: 5392: 5386: 5380: 5360: 5357: 5354: 5351: 5348: 5340: 5336: 5332: 5328: 5324: 5320: 5316: 5312: 5308: 5304: 5300: 5296: 5277: 5266: 5263: 5260: 5254: 5243: 5240: 5237: 5231: 5220: 5217: 5214: 5208: 5191: 5180: 5177: 5168: 5155: 5152: 5149: 5146: 5126: 5123: 5120: 5112: 5108: 5104: 5100: 5081: 5070: 5067: 5055: 5036: 5033: 5021: 5015: 5001: 4995: 4967: 4960: 4954: 4946: 4935: 4923: 4906: 4903: 4891: 4885: 4871: 4865: 4837: 4830: 4824: 4816: 4805: 4793: 4776: 4773: 4761: 4755: 4744: 4738: 4710: 4703: 4697: 4691: 4685: 4673: 4659: 4656: 4649: 4643: 4634: 4628: 4603: 4600: 4593: 4587: 4579: 4568: 4556: 4542: 4539: 4532: 4526: 4517: 4511: 4486: 4483: 4476: 4470: 4462: 4451: 4439: 4425: 4422: 4415: 4409: 4403: 4397: 4372: 4369: 4362: 4356: 4350: 4344: 4332: 4331: 4330: 4316: 4308: 4305: 4302: 4299: 4264: 4250: 4247: 4240: 4234: 4226: 4222: 4215: 4190: 4187: 4180: 4174: 4166: 4162: 4155: 4130: 4127: 4120: 4114: 4108: 4102: 4088: 4075: 4072: 4069: 4063: 4057: 4037: 4034: 4031: 4023: 4019: 4015: 4011: 3992: 3988: 3984: 3981: 3974: 3968: 3960: 3956: 3949: 3940: 3935: 3932: 3925: 3919: 3911: 3907: 3900: 3888: 3887: 3886: 3884: 3880: 3876: 3872: 3868: 3864: 3859: 3845: 3842: 3836: 3830: 3810: 3807: 3804: 3796: 3792: 3788: 3784: 3765: 3762: 3755: 3749: 3743: 3737: 3725: 3724: 3723: 3721: 3717: 3712: 3707: 3703: 3699: 3694: 3677: 3666: 3663: 3643: 3637: 3626: 3623: 3604: 3598: 3581: 3570: 3567: 3555: 3550: 3526: 3520: 3517: 3497: 3494: 3491: 3488: 3476: 3469: 3451: 3448: 3445: 3418: 3415: 3412: 3393: 3375: 3372: 3369: 3342: 3339: 3336: 3317: 3309: 3303: 3297: 3292: 3291:neighbourhood 3285: 3284: 3283: 3266: 3255: 3252: 3229: 3218: 3215: 3203: 3201: 3184: 3168: 3165:The tools of 3160: 3158: 3133: 3128: 3122: 3119: 3114: 3109: 3106: 3100: 3096: 3091: 3088: 3075: 3072: 3069: 3063: 3060: 3053: 3052: 3051: 3034: 3023: 3020: 3017: 3014: 2969: 2953: 2946: 2944: 2931: 2918: 2914: 2910: 2905: 2892: 2889: 2886: 2883: 2858: 2855: 2852: 2849: 2826: 2823: 2820: 2817: 2809: 2806: 2803: 2800: 2794: 2782: 2776: 2773: 2770: 2767: 2759: 2756: 2753: 2750: 2744: 2738: 2735: 2732: 2699: 2680: 2664: 2660: 2655: 2638: 2622: 2603: 2587: 2585: 2553: 2551: 2545: 2538: 2531: 2520: 2514: 2512: 2506: 2502: 2499: 2496: 2492: 2481: 2478: 2475: 2472: 2464: 2461: 2458: 2455: 2449: 2437: 2435: 2429: 2425: 2422: 2415: 2404: 2401: 2398: 2395: 2387: 2384: 2381: 2378: 2372: 2360: 2354: 2351: 2348: 2345: 2337: 2334: 2331: 2328: 2322: 2320: 2314: 2310: 2307: 2304: 2300: 2283: 2277: 2274: 2271: 2268: 2260: 2257: 2254: 2251: 2245: 2243: 2237: 2230: 2227: 2223: 2212: 2209: 2206: 2203: 2200: 2197: 2189: 2186: 2183: 2180: 2174: 2172: 2166: 2162: 2159: 2156: 2152: 2140: 2139: 2138: 2124: 2121: 2118: 2115: 2107: 2104: 2101: 2098: 2075: 2059: 2051: 2049: 2032: 1975: 1972: 1966: 1963: 1960: 1955: 1948: 1943: 1940: 1934: 1931: 1928: 1922: 1920: 1915: 1906: 1899: 1896: 1893: 1880: 1875: 1872: 1868: 1863: 1860: 1855: 1851: 1849: 1844: 1837: 1834: 1831: 1828: 1825: 1822: 1819: 1816: 1814: 1806: 1803: 1800: 1794: 1791: 1780: 1779: 1778: 1765: 1759: 1748: 1745: 1742: 1739: 1736: 1733: 1704: 1701: 1696: 1694: 1686: 1683: 1676: 1673: 1670: 1667: 1665: 1660: 1657: 1654: 1644: 1641: 1638: 1632: 1629: 1626: 1624: 1619: 1616: 1610: 1607: 1604: 1594: 1591: 1588: 1585: 1583: 1578: 1575: 1572: 1562: 1559: 1556: 1550: 1547: 1544: 1542: 1537: 1534: 1528: 1525: 1522: 1508: 1507: 1506: 1493: 1487: 1476: 1473: 1470: 1467: 1464: 1461: 1453: 1445: 1443: 1426: 1396: 1392: 1384: 1361: 1357: 1353: 1341: 1326: 1323: 1315: 1312: 1298: 1284: 1269: 1268: 1267: 1260: 1240: 1237: 1234: 1229: 1226: 1223: 1221: 1216: 1212: 1208: 1201: 1198: 1195: 1190: 1184: 1182: 1177: 1174: 1168: 1162: 1159: 1156: 1153: 1149: 1145: 1135: 1132: 1127: 1121: 1119: 1114: 1110: 1096: 1093: 1088: 1085: 1082: 1080: 1075: 1072: 1069: 1066: 1063: 1060: 1057: 1054: 1047: 1043: 1033: 1030: 1025: 1019: 1017: 1012: 1009: 1003: 997: 994: 984: 981: 976: 970: 968: 963: 960: 954: 948: 945: 934: 933: 932: 915: 904: 901: 878: 841: 833: 831: 829: 821: 816: 814: 798: 783: 780: 776: 771: 769: 765: 761: 758:that is, the 753: 749: 745: 741: 737: 733: 728: 718: 714: 710: 706: 703: 699: 695: 691: 687: 675: 673: 656: 603: 581: 574: 567: 547: 531: 523: 521: 511: 507: 502: 496: 492: 488: 484: 476: 474: 468: 460: 456: 452: 447: 442: 439: 436:, making the 427: 405: 400: 397: 388: 387: 386: 384: 376: 374: 364: 348: 343: 341: 337: 333: 329: 325: 321: 317: 301: 295: 265: 229: 190: 186: 182: 178: 174: 170: 169:real analysis 162: 158: 154: 149: 139: 136: 128: 117: 114: 110: 107: 103: 100: 96: 93: 89: 86: β€“  85: 81: 80:Find sources: 74: 70: 64: 63: 58:This article 56: 52: 47: 46: 41: 19: 7294: 7287: 7276:. Retrieved 7272: 7241: 7145: 6821: 6814:Wheel theory 6777: 6763:Wheel theory 6733:fixed points 6728: 6722: 6715: 6714:PGL(2,  6702:homographies 6691: 6664: 6445: 6275: 6194: 6087: 5930: 5924: 5917: 5913: 5909: 5905: 5899: 5862: 5856: 5850: 5815: 5809: 5777: 5774: 5685: 5611: 5605: 5599: 5592: 5505: 5461: 5412: 5341:, such that 5338: 5334: 5330: 5326: 5322: 5318: 5314: 5310: 5306: 5302: 5298: 5294: 5169: 5110: 5106: 5098: 5059: 4291: 4089: 4024:, such that 4021: 4017: 4013: 4009: 4007: 3882: 3878: 3874: 3870: 3866: 3860: 3797:, such that 3794: 3790: 3786: 3782: 3780: 3719: 3715: 3710: 3705: 3701: 3695: 3559: 3307: 3301: 3295: 3207: 3164: 3148: 2950: 2909:homeomorphic 2906: 2656: 2588: 2581: 2055: 1994: 1725: 1451: 1449: 1380: 1264: 837: 825: 772: 751: 747: 743: 739: 735: 731: 729: 713:group action 694:homeomorphic 685: 679: 579: 572: 565: 527: 503: 487:real numbers 480: 445: 425: 424:for nonzero 423: 380: 344: 189:real numbers 172: 166: 131: 125:January 2023 122: 112: 105: 98: 91: 79: 67:Please help 62:verification 59: 6725:involutions 5936:polynomials 5458:restriction 5313:approaches 5103:limit point 3877:approaches 3714:approaches 2954:extends to 779:dimensional 768:cross-ratio 711:on it. The 684:is a point 365:, in which 7320:Categories 7278:2023-01-22 7217:References 6649:arctangent 5595:continuous 5502:Continuity 5139:such that 3885:, denoted 3722:, denoted 3405:such that 3329:such that 2913:metrizable 2876:such that 750:to 1, and 702:invertible 692:, in fact 438:reciprocal 336:increasing 95:newspapers 7201:contains 7087:∖ 7081:^ 7018:^ 6990:∅ 6967:^ 6956:∈ 6907:∁ 6850:∁ 6797:^ 6665:When the 6630:¯ 6596:^ 6585:∈ 6582:∞ 6527:↦ 6499:¯ 6466:^ 6429:∞ 6381:∞ 6318:^ 6256:^ 6172:∈ 6161:∞ 6150:π 6136:π 6126:⁡ 6092:function 6066:∞ 6046:∞ 6016:^ 5985:^ 5954:^ 5854:tends to 5792:∈ 5757:^ 5746:→ 5708:^ 5697:⊆ 5634:→ 5572:^ 5561:∈ 5548:^ 5537:→ 5531:^ 5475:∪ 5432:∪ 5393:∈ 5358:∩ 5352:∈ 5278:^ 5267:∈ 5255:^ 5244:∈ 5232:^ 5221:⊆ 5209:^ 5198:→ 5192:^ 5150:≠ 5124:∈ 5082:^ 5071:⊆ 5040:∞ 5005:∞ 4999:→ 4971:∞ 4947:− 4943:∞ 4939:→ 4910:∞ 4875:∞ 4872:− 4869:→ 4841:∞ 4813:∞ 4809:→ 4780:∞ 4742:→ 4714:∞ 4689:→ 4638:∞ 4632:→ 4580:− 4576:∞ 4572:→ 4521:∞ 4518:− 4515:→ 4459:∞ 4455:→ 4401:→ 4348:→ 4309:∈ 4227:− 4219:→ 4159:→ 4106:→ 4070:∈ 4035:∈ 3961:− 3953:→ 3904:→ 3843:∈ 3808:∈ 3741:→ 3678:^ 3667:∈ 3638:^ 3627:∈ 3599:^ 3588:→ 3582:^ 3521:∪ 3416:≠ 3340:≠ 3267:^ 3256:⊆ 3230:^ 3219:∈ 3185:^ 3097:∈ 3083:⟺ 3064:∈ 3035:^ 3024:∈ 2970:^ 2859:∈ 2810:∈ 2804:∣ 2795:∪ 2789:∞ 2783:∪ 2760:∈ 2754:∣ 2681:^ 2661:define a 2639:^ 2621:empty set 2604:^ 2560:∞ 2542:∞ 2536:∞ 2479:≤ 2465:∈ 2459:∣ 2450:∪ 2444:∞ 2420:∞ 2402:≤ 2388:∈ 2382:∣ 2373:∪ 2367:∞ 2361:∪ 2352:≤ 2338:∈ 2332:∣ 2290:∞ 2284:∪ 2275:≤ 2261:∈ 2255:∣ 2234:∞ 2210:≤ 2204:≤ 2190:∈ 2184:∣ 2108:∈ 2076:^ 2033:^ 1964:− 1941:− 1897:⋅ 1873:⋅ 1835:⋅ 1823:⋅ 1795:⋅ 1760:^ 1749:∈ 1690:∞ 1687:⋅ 1674:⋅ 1658:⋅ 1642:⋅ 1633:⋅ 1617:⋅ 1608:⋅ 1488:^ 1477:∈ 1427:^ 1346:∞ 1338:∞ 1330:∞ 1327:⋅ 1313:⋅ 1310:∞ 1302:∞ 1299:− 1296:∞ 1288:∞ 1282:∞ 1238:≠ 1199:≠ 1188:∞ 1175:⋅ 1172:∞ 1166:∞ 1163:⋅ 1139:∞ 1136:≠ 1125:∞ 1107:∞ 1100:∞ 1097:≠ 1073:⋅ 1061:⋅ 1052:∞ 1037:∞ 1034:≠ 1023:∞ 1010:− 1007:∞ 1001:∞ 998:− 988:∞ 985:≠ 974:∞ 958:∞ 952:∞ 916:^ 905:∈ 879:^ 657:^ 604:^ 548:^ 434:1 / ∞ = 0 430:1 / 0 = ∞ 409:∞ 340:unbounded 326:of every 296:^ 266:∗ 236:∞ 230:∪ 181:real line 7341:Infinity 6939:for all 6747:See also 6737:negation 6731:has two 6687:midpoint 6448:codomain 6340:and all 6083:constant 5922:, where 5860:through 5456:and the 5373:implies 5317:through 5305: ( 4050:implies 3869: ( 3823:implies 3704: ( 3492:∉ 3167:calculus 3161:Calculus 2842:for all 2663:topology 2619:and the 2058:interval 705:matrices 676:Geometry 584:. Since 577:or that 441:function 328:sequence 6090:tangent 5097:. Then 2698:bounded 187:of the 179:of the 109:scholar 7302:  6613:domain 5900:Every 3551:Limits 2917:metric 840:subset 828:limits 746:to 0, 707:has a 582:< ∞ 575:> ∞ 459:binary 171:, the 153:circle 111:  104:  97:  90:  82:  38:, see 7207:0 / 0 6769:Notes 6276:Many 6195:then 5309:) as 5101:is a 3873:) as 3708:) as 3698:limit 3481:, if 3473:is a 3299:, if 3289:is a 2985:from 760:group 530:order 524:Order 483:field 467:slope 463:0 β‹… ∞ 455:field 324:limit 116:JSTOR 102:books 7300:ISBN 7002:and 6882:and 6739:and 6727:. A 6706:ring 6346:sine 5934:are 5928:and 5615:and 5170:Let 5060:Let 4203:and 3861:The 3696:The 3656:and 3560:Let 3510:and 3431:and 3355:and 3245:and 3208:Let 3153:and 2887:< 2824:< 2774:< 2659:base 2122:< 1381:The 738:and 528:The 516:and 444:1 / 432:and 369:and 357:and 338:and 334:are 320:ends 88:news 34:and 6692:As 6203:tan 6123:tan 6100:tan 6058:at 5969:to 5866:is 5848:as 5686:If 5627:lim 5597:at 5593:is 5464:to 5460:of 5421:on 5337:of 5329:of 5321:is 5105:of 4992:lim 4932:lim 4862:lim 4802:lim 4735:lim 4682:lim 4625:lim 4565:lim 4508:lim 4448:lim 4394:lim 4341:lim 4212:lim 4152:lim 4099:lim 4020:of 4012:of 3946:lim 3897:lim 3865:of 3793:of 3785:of 3734:lim 3718:is 3700:of 3293:of 2665:on 2137:): 863:of 784:of 754:to 568:β‰  ∞ 485:of 280:or 185:set 167:In 71:by 7322:: 7271:. 7251:^ 7225:^ 6720:. 6689:. 6651:. 6085:. 5912:)/ 5807:, 5293:, 4263:. 3858:. 3693:. 3282:. 3157:. 3050:: 1442:. 813:. 734:, 727:. 672:. 520:. 518:βˆ’βˆž 514:+∞ 501:. 473:. 449:a 385:: 371:βˆ’βˆž 367:+∞ 353:, 342:. 191:, 36:β€“βˆž 32:+∞ 7308:. 7281:. 7203:0 7189:] 7186:1 7183:, 7180:0 7177:[ 7173:/ 7169:] 7166:1 7163:, 7160:0 7157:[ 7128:] 7125:a 7122:, 7119:a 7116:( 7096:} 7093:a 7090:{ 7077:R 7053:) 7050:a 7047:, 7044:a 7041:( 7014:R 6963:R 6953:b 6950:, 6947:a 6927:] 6924:a 6921:, 6918:b 6915:( 6912:= 6903:] 6899:b 6896:, 6893:a 6890:( 6870:) 6867:a 6864:, 6861:b 6858:( 6855:= 6846:] 6842:b 6839:, 6836:a 6833:[ 6816:. 6793:R 6718:) 6716:R 6635:. 6626:R 6592:R 6561:R 6540:. 6535:x 6532:1 6524:x 6504:. 6495:R 6462:R 6432:. 6409:, 6405:R 6384:. 6361:, 6357:R 6324:. 6314:R 6289:R 6262:. 6252:R 6228:, 6224:R 6180:, 6176:Z 6169:n 6158:= 6154:) 6147:n 6144:+ 6139:2 6130:( 6069:, 6022:. 6012:R 5981:R 5950:R 5931:Q 5925:P 5920:) 5918:x 5916:( 5914:Q 5910:x 5908:( 5906:P 5886:. 5883:) 5880:p 5877:( 5874:f 5863:A 5857:p 5851:x 5836:) 5833:x 5830:( 5827:f 5816:p 5810:f 5795:A 5789:p 5778:A 5753:R 5743:A 5740:: 5737:f 5714:, 5704:R 5694:A 5671:. 5668:) 5665:p 5662:( 5659:f 5656:= 5652:) 5649:x 5646:( 5643:f 5637:p 5631:x 5612:p 5606:f 5600:p 5578:. 5568:R 5558:p 5554:, 5544:R 5527:R 5520:: 5517:f 5487:. 5484:} 5481:p 5478:{ 5472:A 5462:f 5444:, 5441:} 5438:p 5435:{ 5429:A 5399:. 5396:B 5390:) 5387:x 5384:( 5381:f 5361:C 5355:A 5349:x 5339:p 5335:C 5331:L 5327:B 5323:L 5319:A 5315:p 5311:x 5307:x 5303:f 5299:A 5295:p 5274:R 5264:p 5261:, 5251:R 5241:L 5238:, 5228:R 5218:A 5215:, 5205:R 5188:R 5181:: 5178:f 5156:. 5153:p 5147:y 5127:A 5121:y 5111:p 5107:A 5099:p 5078:R 5068:A 5037:+ 5034:= 5029:| 5025:) 5022:x 5019:( 5016:f 5012:| 5002:+ 4996:x 4968:= 4964:) 4961:x 4958:( 4955:f 4936:x 4907:+ 4904:= 4899:| 4895:) 4892:x 4889:( 4886:f 4882:| 4866:x 4838:= 4834:) 4831:x 4828:( 4825:f 4817:+ 4806:x 4777:+ 4774:= 4769:| 4765:) 4762:x 4759:( 4756:f 4752:| 4745:p 4739:x 4711:= 4707:) 4704:x 4701:( 4698:f 4692:p 4686:x 4660:L 4657:= 4653:) 4650:x 4647:( 4644:f 4635:+ 4629:x 4604:L 4601:= 4597:) 4594:x 4591:( 4588:f 4569:x 4543:L 4540:= 4536:) 4533:x 4530:( 4527:f 4512:x 4487:L 4484:= 4480:) 4477:x 4474:( 4471:f 4463:+ 4452:x 4426:L 4423:= 4419:) 4416:x 4413:( 4410:f 4404:p 4398:x 4373:L 4370:= 4366:) 4363:x 4360:( 4357:f 4351:p 4345:x 4317:, 4313:R 4306:L 4303:, 4300:p 4276:R 4251:L 4248:= 4244:) 4241:x 4238:( 4235:f 4223:p 4216:x 4191:L 4188:= 4184:) 4181:x 4178:( 4175:f 4167:+ 4163:p 4156:x 4131:L 4128:= 4124:) 4121:x 4118:( 4115:f 4109:p 4103:x 4076:. 4073:A 4067:) 4064:x 4061:( 4058:f 4038:B 4032:x 4022:p 4018:B 4014:L 4010:A 3993:, 3989:) 3985:L 3982:= 3978:) 3975:x 3972:( 3969:f 3957:p 3950:x 3941:( 3936:L 3933:= 3929:) 3926:x 3923:( 3920:f 3912:+ 3908:p 3901:x 3883:L 3879:p 3875:x 3871:x 3867:f 3846:A 3840:) 3837:x 3834:( 3831:f 3811:B 3805:x 3795:p 3791:B 3787:L 3783:A 3766:L 3763:= 3759:) 3756:x 3753:( 3750:f 3744:p 3738:x 3720:L 3716:p 3711:x 3706:x 3702:f 3674:R 3664:L 3644:, 3634:R 3624:p 3605:, 3595:R 3578:R 3571:: 3568:f 3546:. 3544:x 3530:} 3527:x 3524:{ 3518:A 3498:, 3495:A 3489:x 3479:x 3471:A 3467:. 3455:] 3452:x 3449:, 3446:y 3443:( 3433:A 3419:x 3413:y 3403:y 3399:x 3395:A 3391:. 3379:) 3376:y 3373:, 3370:x 3367:[ 3357:A 3343:x 3337:y 3327:y 3323:x 3319:A 3315:. 3313:x 3308:B 3302:A 3296:x 3287:A 3263:R 3253:A 3226:R 3216:x 3181:R 3155:∞ 3151:0 3134:, 3129:] 3123:a 3120:1 3115:, 3110:b 3107:1 3101:[ 3092:x 3089:1 3079:] 3076:b 3073:, 3070:a 3067:[ 3061:x 3031:R 3021:b 3018:, 3015:a 2994:R 2966:R 2932:. 2928:R 2893:. 2890:b 2884:a 2863:R 2856:b 2853:, 2850:a 2830:} 2827:a 2821:x 2818:, 2814:R 2807:x 2801:x 2798:{ 2792:} 2786:{ 2780:} 2777:x 2771:b 2768:, 2764:R 2757:x 2751:x 2748:{ 2745:= 2742:) 2739:a 2736:, 2733:b 2730:( 2709:R 2677:R 2635:R 2600:R 2563:} 2557:{ 2554:= 2546:] 2539:, 2532:[ 2524:} 2521:a 2518:{ 2515:= 2507:] 2503:a 2500:, 2497:a 2493:[ 2485:} 2482:a 2476:x 2473:, 2469:R 2462:x 2456:x 2453:{ 2447:} 2441:{ 2438:= 2430:] 2426:a 2423:, 2416:[ 2408:} 2405:a 2399:x 2396:, 2392:R 2385:x 2379:x 2376:{ 2370:} 2364:{ 2358:} 2355:x 2349:b 2346:, 2342:R 2335:x 2329:x 2326:{ 2323:= 2315:] 2311:a 2308:, 2305:b 2301:[ 2293:} 2287:{ 2281:} 2278:x 2272:a 2269:, 2265:R 2258:x 2252:x 2249:{ 2246:= 2238:] 2231:, 2228:a 2224:[ 2216:} 2213:b 2207:x 2201:a 2198:, 2194:R 2187:x 2181:x 2178:{ 2175:= 2167:] 2163:b 2160:, 2157:a 2153:[ 2125:b 2119:a 2116:, 2112:R 2105:b 2102:, 2099:a 2072:R 2029:R 2004:R 1976:b 1973:+ 1970:) 1967:b 1961:a 1958:( 1949:= 1944:b 1938:) 1935:b 1932:+ 1929:a 1926:( 1923:= 1916:a 1907:b 1903:) 1900:b 1894:a 1891:( 1881:= 1876:b 1869:) 1864:b 1861:a 1856:( 1852:= 1845:a 1838:c 1832:a 1829:+ 1826:b 1820:a 1817:= 1810:) 1807:c 1804:+ 1801:b 1798:( 1792:a 1766:. 1756:R 1746:c 1743:, 1740:b 1737:, 1734:a 1705:0 1702:a 1697:= 1684:a 1677:a 1671:b 1668:= 1661:b 1655:a 1648:) 1645:c 1639:b 1636:( 1630:a 1627:= 1620:c 1614:) 1611:b 1605:a 1602:( 1595:a 1592:+ 1589:b 1586:= 1579:b 1576:+ 1573:a 1566:) 1563:c 1560:+ 1557:b 1554:( 1551:+ 1548:a 1545:= 1538:c 1535:+ 1532:) 1529:b 1526:+ 1523:a 1520:( 1494:. 1484:R 1474:c 1471:, 1468:b 1465:, 1462:a 1423:R 1397:x 1393:e 1362:0 1358:/ 1354:0 1342:/ 1324:0 1316:0 1285:+ 1241:0 1235:a 1230:, 1227:0 1224:= 1217:a 1213:/ 1209:0 1202:0 1196:a 1191:, 1185:= 1178:a 1169:= 1160:a 1157:= 1154:0 1150:/ 1146:a 1133:a 1128:, 1122:= 1115:a 1111:/ 1094:a 1089:, 1086:0 1083:= 1076:a 1070:0 1067:= 1064:0 1058:a 1055:= 1048:/ 1044:a 1031:a 1026:, 1020:= 1013:a 1004:= 995:a 982:a 977:, 971:= 964:a 961:+ 955:= 949:+ 946:a 912:R 902:a 875:R 850:R 799:2 794:R 756:∞ 752:R 748:Q 744:P 740:R 736:Q 732:P 725:∞ 721:0 682:∞ 653:R 628:R 600:R 586:∞ 580:a 573:a 566:a 544:R 499:∞ 471:∞ 446:x 426:a 406:= 401:0 398:a 359:∞ 355:1 351:0 302:. 292:R 261:R 239:} 233:{ 226:R 215:∞ 200:R 163:. 138:) 132:( 127:) 123:( 113:Β· 106:Β· 99:Β· 92:Β· 65:. 42:. 20:)

Index

Projected reals
Extended real number line

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circle
stereographic projection
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real analysis
one-point compactification
real line
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real numbers
point at infinity
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limit
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increasing
unbounded
real projective line

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