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Poincaré disk model

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6766: 31: 277:, so that the linear dilatation of any body is proportional to its absolute temperature. Finally, I shall assume that a body transported from one point to another of different temperature is instantaneously in thermal equilibrium with its new environment. ... If they construct a geometry, it will not be like ours, which is the study of the movements of our invariable solids; it will be the study of the changes of position which they will have thus distinguished, and will be 'non-Euclidean displacements,' and 39: 1025: 6765: 5332:(the set of all points in a plane that are at a given distance from a given point, its center) is a circle completely inside the disk not touching or intersecting its boundary. The hyperbolic center of the circle in the model does not in general correspond to the Euclidean center of the circle, but they are on the same radius of the Poincare disk. (The Euclidean center is always closer to the center of the disk than the hyperbolic center.) 303: 6870: 1403: 3955: 5363: 733: 1644: 7261: 2317: 3541: 1020:{\displaystyle {\begin{aligned}d(u,v)&=\operatorname {arcosh} (1+\delta (u,v))\\&=2\operatorname {arsinh} {\sqrt {\frac {\delta (u,v)}{2}}}\\\,&=2\ln {\frac {\lVert u-v\rVert +{\sqrt {\lVert u\rVert ^{2}\lVert v\rVert ^{2}-2u\cdot v+1}}}{\sqrt {(1-\lVert u\rVert ^{2})(1-\lVert v\rVert ^{2})}}}.\end{aligned}}} 5400:), is a circle inside the disk that is tangent to the boundary circle of the disk. The point where it touches the boundary circle is not part of the horocycle. It is an ideal point and is the hyperbolic center of the horocycle. It is also the point to which all the perpendicular geodesics converge. 1030:
Such a distance function is defined for any two vectors of norm less than one, and makes the set of such vectors into a metric space which is a model of hyperbolic space of constant curvature −1. The model has the conformal property that the angle between two intersecting curves in hyperbolic space
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In the Poincaré disk model, the Euclidean points representing opposite "ends" of a horocycle converge to its center on the boundary circle, but in the hyperbolic plane every point of a horocycle is infinitely far from its center, and opposite ends of the horocycle are not connected. (Euclidean
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Milnor, John W. "Hyperbolic geometry: the first 150 years." Bulletin of the American Mathematical Society 6, no. 1 (1982): 9-24. B. Riemann, "Ueber die Hypothesen welche der Geometrie zu Grunde liegen", Abh. K. G. Wiss. Göttingen 13 (from his Inaugural Address of 1854).
2131: 3950:{\displaystyle {\begin{aligned}x^{2}+y^{2}&{}+{\frac {u_{2}(v_{1}^{2}+v_{2}^{2}+1)-v_{2}(u_{1}^{2}+u_{2}^{2}+1)}{u_{1}v_{2}-u_{2}v_{1}}}x\\&{}+{\frac {v_{1}(u_{1}^{2}+u_{2}^{2}+1)-u_{1}(v_{1}^{2}+v_{2}^{2}+1)}{u_{1}v_{2}-u_{2}v_{1}}}y+1=0\,.\end{aligned}}} 696: 6076: 1769: 5765: 5419: 533: 6512: 6343: 189:"Suppose, for example, a world enclosed in a large sphere and subject to the following laws: The temperature is not uniform; it is greatest at their centre, and gradually decreases as we move towards the circumference of the sphere, where it is 6745: 6843: 5619: 1870: 5346:(the set of all points in a plane that are on one side and at a given distance from a given line, its axis) is a Euclidean circle arc or chord of the boundary circle that intersects the boundary circle at a positive but non- 1639:{\displaystyle ds^{2}=4{\frac {\sum _{i}dx_{i}^{2}}{\left(1-\sum _{i}x_{i}^{2}\right)^{2}}}={\frac {4\,\lVert d\mathbf {x} \rVert {\vphantom {l}}^{2}}{{\bigl (}1-\lVert \mathbf {x} \rVert {\vphantom {l}}^{2}{\bigr )}^{2}}}} 5124: 1108: 1227: 6849: 6848: 6845: 6844: 6850: 4984: 4885: 4786: 4610: 1981: 3974: 3546: 285:
Poincaré's disk was an important piece of evidence for the hypothesis that the choice of spatial geometry is conventional rather than factual, especially in the influential philosophical discussions of
4684: 4418: 2312:{\displaystyle \Omega =d\omega +\omega \wedge \omega =d\omega +0={\frac {-4\,dx\wedge dy}{{\bigl (}1-|\mathbf {x} |{\vphantom {l}}^{2}{\bigr )}^{2}}}{\begin{pmatrix}0&1\\-1&0\end{pmatrix}}.} 5963: 179:. Henri Poincaré employed it in his 1882 treatment of hyperbolic, parabolic and elliptic functions, but it became widely known following Poincaré's presentation in his 1905 philosophical treatise, 6847: 738: 6122:
is a complex number of norm less than one representing a point of the Poincaré disk model, then the corresponding point of the half-plane model is given by the inverse of the Cayley transform:
2399: 1953: 417: 5936: 6619: 6615: 4305: 1184: 3506: 1128: 570: 6175: 5240: 5182: 1667: 725: 5635: 4472: 6533:. If we have a point on the upper sheet of the hyperboloid of the hyperboloid model, thereby defining a point in the hyperboloid model, we may project it onto the hyperplane 185:. There he describes a world, now known as the Poincaré disk, in which space was Euclidean, but which appeared to its inhabitants to satisfy the axioms of hyperbolic geometry: 7027:
Eugenio Beltrami. "Teoria fondamentale degli spazii di curvatura costante", Annali di mat. ser. II 2, 232-255 (Op. Mat. 1, 406-429; Ann. École Norm. Sup. 6 (1869), 345-375).
5814: 4511: 1222: 6359: 6190: 5858: 271: 1392: 3248: 3178: 2803: 2733: 2660: 2610: 4348: 3104: 2536: 2485: 1973: 1908: 1041: 5266:: circles, horocycles, hypercycles, and geodesics (or "hyperbolic lines"). In the Poincaré disk model, all of these are represented by straight lines or circles. 3077: 3029: 6120: 5958: 5881: 3416: 3393: 3373: 3353: 3333: 3310: 3290: 3270: 3220: 3200: 3150: 3128: 3051: 3002: 2971: 2948: 2928: 2908: 2888: 2865: 2845: 2825: 2775: 2755: 2702: 2682: 2632: 2578: 2556: 2509: 2452: 2432: 231: 211: 3431:
is to find a line through two given points. In the Poincaré disk model, lines in the plane are defined by portions of circles having equations of the form
1780: 5502: 4237:, by means of a formula. Since the ideal points are the same in the Klein model and the Poincaré disk model, the formulas are identical for each model. 5883:
is a vector of norm less than one representing a point of the Poincaré disk model, then the corresponding point of the Klein disk model is given by:
537:
The vertical bars indicate Euclidean length of the line segment connecting the points between them in the model (not along the circle arc); ln is the
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of norm less than one representing a point of the Beltrami–Klein model, the corresponding point of the Poincaré disk model is given by:
4893: 4794: 4695: 4519: 2115:{\displaystyle \omega ={\frac {2(y\,dx-x\,dy)}{1-|\mathbf {x} |{\vphantom {l}}^{2}}}{\begin{pmatrix}0&1\\-1&0\end{pmatrix}},} 7009: 4198:{\displaystyle x^{2}+y^{2}+{\frac {2(u_{2}-v_{2})}{u_{1}v_{2}-u_{2}v_{1}}}x+{\frac {2(v_{1}-u_{1})}{u_{1}v_{2}-u_{2}v_{1}}}y+1=0\,.} 1356:{\displaystyle \ln \left({\frac {1+r}{1-r}}\cdot {\frac {1-r'}{1+r'}}\right)=2(\operatorname {artanh} r-\operatorname {artanh} r').} 5442:(also known as the Beltrami–Klein model) and the Poincaré disk model are both models that project the whole hyperbolic plane in a 7265: 6911: 5886: 5342: 6565: 6537: = 0 by intersecting it with a line drawn through . The result is the corresponding point of the Poincaré disk model. 4621: 140:, because his rediscovery of this representation fourteen years later became better known than the original work of Beltrami. 4356: 3535:
in the disk which do not lie on a diameter, we can solve for the circle of this form passing through both points, and obtain
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explored the concept of representing infinity on a two-dimensional plane. Discussions with Canadian mathematician
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The group of orientation preserving isometries of the disk model is given by the projective special unitary group
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Specializing to the case where one of the points is the origin and the Euclidean distance between the points is
691:{\displaystyle \delta (u,v)=2{\frac {\lVert u-v\rVert ^{2}}{(1-\lVert u\rVert ^{2})(1-\lVert v\rVert ^{2})}}\,,} 6800: 6750: 6071:{\displaystyle u={\frac {s}{1+{\sqrt {1-s\cdot s}}}}={\frac {\left(1-{\sqrt {1-s\cdot s}}\right)s}{s\cdot s}}.} 5459: 4262: 281:. So that beings like ourselves, educated in such a world, will not have the same geometry as ours." (pp.65-68) 3437: 1764:{\displaystyle e_{i}={\frac {1}{2}}{\Bigl (}1-|\mathbf {x} |^{2}{\Bigr )}{\frac {\partial }{\partial x^{i}}},} 330: 30: 6928:, a roguelike game, uses the hyperbolic plane for its world geometry, and also uses the Poincaré disk model. 5760:{\textstyle \left({\frac {x}{1+{\sqrt {1-x^{2}-y^{2}}}}}\ ,\ \ {\frac {y}{1+{\sqrt {1-x^{2}-y^{2}}}}}\right)} 1113: 7216: 5455: 3511:
which is the general form of a circle orthogonal to the unit circle, or else by diameters. Given two points
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intuition can be misleading because the scale of the model increases to infinity at the boundary circle.)
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are points on the boundary of the disk not lying at the endpoints of a diameter, the above simplifies to
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Animation of a partial {7,3} hyperbolic tiling of the hyperboloid rotated into the Poincare perspective.
6541: 528:{\displaystyle d(p,q)=\ln {\frac {\left|aq\right|\,\left|pb\right|}{\left|ap\right|\,\left|qb\right|}}.} 38: 6836:. The red geodesic in the Poincaré disk model projects to the brown geodesic on the green hyperboloid. 4429: 233:
the distance of the point considered from the centre, the absolute temperature will be proportional to
6507:{\textstyle \left({\frac {2x}{x^{2}+(1+y)^{2}}}\ ,\ {\frac {x^{2}+y^{2}-1}{x^{2}+(1+y)^{2}}}\right)\,} 6338:{\textstyle \left({\frac {2x}{x^{2}+(1-y)^{2}}}\ ,\ {\frac {1-x^{2}-y^{2}}{x^{2}+(1-y)^{2}}}\right)\,} 7107:
Carus, A. W.; Friedman, Michael; Kienzler, Wolfgang; Richardson, Alan; Schlotter, Sven (2019-06-25).
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and the fact that these are unit vectors we may rewrite the above expressions purely in terms of the
1141: 4256:, then we are merely finding the angle between two unit vectors, and the formula for the angle θ is 6937: 6740:{\displaystyle (t,x_{i})={\frac {\left(1+\sum {y_{i}^{2}},\,2y_{i}\right)}{1-\sum {y_{i}^{2}}}}\,.} 5773: 5447: 5427: 5413: 4480: 1189: 1135: 63: 7069: 6967: 5819: 5251: 1407: 323: 236: 160: 133: 6952: 1881: 7001: 7141: 7114: 7061: 7005: 6962: 6902: 6874: 6527: 6096: 5393: 5385: 3428: 538: 137: 5476:
When projecting the same lines in both models on one disk both lines go through the same two
4333: 1958: 1893: 341:
inside the disk, the unique hyperbolic line connecting them intersects the boundary at two
7051: 6993: 6917: 6889: 6086: 5466: 5451: 5439: 5307: 5259: 3107: 2488: 291: 176: 172: 125: 67: 7177:"Comparing metric tensors of the Poincare and the Klein disk models of hyperbolic geometry" 5443: 2977:
If P and Q are on a diameter of the boundary circle that diameter is the hyperbolic line.
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with the usual Euclidean norm, both of which have norm less than 1, then we may define an
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An advantage of the Klein disk model is that lines in this model are Euclidean straight
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of the chord in the Klein disk model is the center of the circle that contains the
4214: 79: 7135: 7108: 6523: 5477: 5397: 5371: 5362: 5351: 5347: 5262:. In the hyperbolic plane, there are 4 distinct types of generalized circles or 4994: 1890:, the connection forms are given by the unique skew-symmetric matrix of 1-forms 342: 155:-dimensional hyperbolic geometry in which the points of the geometry are in the 117: 5370:
and some red normals. The normals converge asymptotically to the upper central
5119:{\displaystyle P=(u-v)\cdot (s-t)+(u\cdot t)(v\cdot s)-(u\cdot s)(v\cdot t)\,.} 6925: 6905:, which are regular tilings of the hyperbolic plane. Escher's wood engravings 5418: 5288: 83: 7110:
Rudolf Carnap: Early Writings: The Collected Works of Rudolf Carnap, Volume 1
7065: 1103:{\displaystyle \ln \left({\frac {1+r}{1-r}}\right)=2\operatorname {artanh} r} 17: 6826: 5380: 322:
consist of all arcs of Euclidean circles contained within the disk that are
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An orthonormal frame with respect to this Riemannian metric is given by
7056: 273:. Further, I shall suppose that in this world all bodies have the same 98: 7039: 5328: 5255: 175:
in an 1854 lecture (published 1868), which inspired an 1868 paper by
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demonstrate this concept between 1958 and 1960, the final one being
7197:"Mapping the Poincare disk model to the Poincare half plane model" 6868: 5417: 5361: 4979:{\displaystyle R=(s-t)\cdot (s-t)-(s\wedge t)\cdot (s\wedge t)\,.} 4880:{\displaystyle Q=(u-v)\cdot (u-v)-(u\wedge v)\cdot (u\wedge v)\,,} 4781:{\displaystyle P=(u-v)\cdot (s-t)-(u\wedge v)\cdot (s\wedge t)\,,} 4605:{\displaystyle R=(s-t)\cdot (s-t)-(s\wedge t)\cdot (s\wedge t)\,.} 1401: 301: 37: 29: 6996:
The Road To Reality: A Complete Guide to the Laws of the Universe
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denotes the usual Euclidean norm. Then the distance function is
4615:
If both chords are not diameters, the general formula obtains
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are the Cartesian coordinates of the ambient Euclidean space.
5254:(curves of constant curvature) are lines and circles. On the 326:
to the boundary of the disk, plus all diameters of the disk.
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to the hemisphere model while the Poincaré disk model is a
5350:. Its axis is the hyperbolic line that shares the same two 128:
who used these models to show that hyperbolic geometry was
7165:. Translated by Cole, M.; Levy, S. Springer. p. 339. 6799:. It can be used to construct a Poincaré disk model as a 6771:
The hyperboloid model can be represented as the equation
5280:
that is inside the disk and tangent to the boundary is a
4679:{\displaystyle \cos ^{2}(\theta )={\frac {P^{2}}{QR}}\,,} 6915:
in 1960. According to Bruno Ernst, the best of them is
5414:
Hyperbolic geometry § Connection between the models
1886:
In two dimensions, with respect to these frames and the
4413:{\displaystyle \cos ^{2}(\theta )={\frac {P^{2}}{QR}},} 7240:
Teoria fondamentale degli spazii di curvatura costante
6362: 6193: 5638: 5505: 5480:. (the ideal points remain on the same spot) also the 5314:
that goes through the center is a hyperbolic line; and
2272: 2075: 6622: 6568: 6128: 6108: 5966: 5946: 5889: 5869: 5822: 5776: 5469:. A disadvantage is that the Klein disk model is not 5193: 5135: 5006: 4896: 4797: 4698: 4624: 4522: 4483: 4432: 4359: 4336: 4265: 3977: 3544: 3440: 3404: 3381: 3361: 3341: 3321: 3298: 3278: 3258: 3228: 3208: 3188: 3158: 3138: 3116: 3087: 3062: 3039: 3014: 2990: 2959: 2936: 2916: 2896: 2876: 2853: 2833: 2813: 2783: 2763: 2743: 2713: 2690: 2670: 2640: 2620: 2590: 2566: 2544: 2519: 2497: 2468: 2440: 2420: 2331: 2134: 1984: 1961: 1920: 1896: 1783: 1670: 1431: 1369: 1230: 1192: 1144: 1138:. If the two points lie on the same radius and point 1116: 1044: 736: 707: 573: 420: 239: 219: 199: 5317:
that does not go through the center is a hypercycle.
2322:Therefore, the curvature of the hyperbolic disk is 7096:. Robarts - University of Toronto. London W. Scott. 5298:that intersects the boundary non-orthogonally is a 7161:Berger, Marcel (1987) . "9.6 The Poincaré Model". 6739: 6609: 6506: 6337: 6169: 6114: 6070: 5952: 5930: 5875: 5852: 5808: 5759: 5613: 5234: 5176: 5118: 4978: 4879: 4780: 4678: 4604: 4505: 4466: 4412: 4342: 4299: 4197: 3949: 3500: 3410: 3387: 3367: 3347: 3327: 3304: 3284: 3264: 3242: 3214: 3194: 3172: 3144: 3122: 3098: 3071: 3045: 3023: 2996: 2965: 2942: 2922: 2902: 2882: 2859: 2839: 2819: 2797: 2769: 2749: 2727: 2696: 2676: 2654: 2626: 2604: 2572: 2550: 2530: 2503: 2479: 2446: 2426: 2394:{\displaystyle K=\Omega _{2}^{1}(e_{1},e_{2})=-1.} 2393: 2311: 2114: 1967: 1947: 1902: 1864: 1763: 1638: 1386: 1355: 1216: 1178: 1122: 1102: 1019: 719: 690: 527: 265: 225: 205: 6825:, projecting the upper half hyperboloid onto the 2538:be the inversion in the boundary circle of point 1731: 1696: 2454:not on a diameter of the boundary circle can be 1948:{\displaystyle 0=d\theta +\omega \wedge \theta } 1914:-free, i.e., that satisfies the matrix equation 353:. Label them so that the points are, in order, 193:. The law of this temperature is as follows: If 5408:Relation to other models of hyperbolic geometry 3418:that is inside the disk is the hyperbolic line. 2973:that is inside the disk is the hyperbolic line. 5354:. This is also known as an equidistant curve. 2414:The unique hyperbolic line through two points 6562:) on the plane, the conversion formulas are: 4240:If both models' lines are diameters, so that 2253: 2206: 1622: 1579: 1363:This reduces to the previous special case if 8: 7242:, Annali. di Mat., ser II 2 (1868), 232–255. 5396:, all converging asymptotically to the same 1598: 1590: 1554: 1543: 995: 988: 967: 960: 917: 910: 901: 894: 886: 874: 714: 708: 669: 662: 641: 634: 614: 601: 97:, the quotient of the special unitary group 34:Poincaré disk with hyperbolic parallel lines 5931:{\displaystyle s={\frac {2u}{1+u\cdot u}}.} 6901:around 1956 inspired Escher's interest in 6610:{\displaystyle y_{i}={\frac {x_{i}}{1+t}}} 6087:Cayley transform § Complex homography 7055: 6733: 6723: 6718: 6713: 6692: 6684: 6674: 6669: 6664: 6648: 6636: 6621: 6588: 6582: 6573: 6567: 6503: 6489: 6464: 6446: 6433: 6426: 6408: 6383: 6368: 6361: 6334: 6320: 6295: 6283: 6270: 6257: 6239: 6214: 6199: 6192: 6135: 6127: 6107: 6081:Relation to the Poincaré half-plane model 6024: 6010: 5985: 5973: 5965: 5945: 5896: 5888: 5868: 5821: 5794: 5781: 5775: 5741: 5728: 5716: 5704: 5681: 5668: 5656: 5644: 5637: 5597: 5584: 5563: 5545: 5532: 5511: 5504: 5228: 5222: 5192: 5170: 5164: 5134: 5112: 5005: 4972: 4895: 4873: 4796: 4774: 4697: 4672: 4656: 4650: 4629: 4623: 4598: 4521: 4499: 4482: 4460: 4431: 4391: 4385: 4364: 4358: 4335: 4300:{\displaystyle \cos(\theta )=u\cdot s\,.} 4293: 4264: 4191: 4167: 4157: 4144: 4134: 4119: 4106: 4093: 4078: 4068: 4055: 4045: 4030: 4017: 4004: 3995: 3982: 3976: 3939: 3915: 3905: 3892: 3882: 3861: 3856: 3843: 3838: 3825: 3803: 3798: 3785: 3780: 3767: 3760: 3755: 3736: 3726: 3713: 3703: 3682: 3677: 3664: 3659: 3646: 3624: 3619: 3606: 3601: 3588: 3581: 3576: 3566: 3553: 3545: 3543: 3494: 3458: 3445: 3439: 3403: 3380: 3360: 3340: 3320: 3297: 3277: 3257: 3227: 3207: 3187: 3157: 3137: 3115: 3086: 3061: 3038: 3013: 2989: 2958: 2935: 2915: 2895: 2875: 2852: 2832: 2812: 2782: 2762: 2742: 2712: 2689: 2669: 2639: 2619: 2589: 2565: 2543: 2518: 2496: 2467: 2439: 2419: 2373: 2360: 2347: 2342: 2330: 2267: 2258: 2252: 2251: 2244: 2234: 2233: 2227: 2222: 2217: 2205: 2204: 2186: 2177: 2133: 2070: 2061: 2051: 2050: 2044: 2039: 2034: 2016: 2003: 1991: 1983: 1960: 1919: 1895: 1853: 1845: 1836: 1826: 1825: 1819: 1814: 1809: 1797: 1788: 1782: 1749: 1736: 1730: 1729: 1723: 1718: 1712: 1707: 1695: 1694: 1684: 1675: 1669: 1627: 1621: 1620: 1613: 1603: 1602: 1593: 1578: 1577: 1569: 1559: 1558: 1549: 1542: 1536: 1525: 1514: 1509: 1499: 1476: 1471: 1458: 1451: 1439: 1430: 1368: 1271: 1242: 1229: 1191: 1143: 1115: 1055: 1043: 998: 970: 920: 904: 892: 871: 854: 821: 737: 735: 706: 684: 672: 644: 617: 598: 572: 502: 467: 448: 419: 257: 244: 238: 218: 198: 7000:. Great Britain: Jonathan Cape. p.  6522:The Poincaré disk model, as well as the 5273:that is completely inside the disk is a 3501:{\displaystyle x^{2}+y^{2}+ax+by+1=0\,,} 6984: 6761: 4326:, the formula becomes, in terms of the 1422:of the Poincaré disk model is given by 1410:' model view of the hyperbolic regular 1123:{\displaystyle \operatorname {artanh} } 1031:is the same as the angle in the model. 6170:{\displaystyle s={\frac {u+i}{iu+1}}.} 5426:), and their relations with the other 171:The disk model was first described by 5499:) in the Poincaré disk model maps to 5235:{\displaystyle R=(1-s\cdot t)^{2}\,.} 5177:{\displaystyle Q=(1-u\cdot v)^{2}\,,} 4213:We may compute the angle between the 7: 7085: 7083: 5473:(circles and angles are distorted). 5450:through a projection on or from the 720:{\displaystyle \lVert \cdot \rVert } 6973:Uniform tilings in hyperbolic plane 279:this will be non-Euclidean geometry 82:contained within the disk that are 4229:, and the arc whose endpoints are 2339: 2135: 1742: 1738: 1186:lies between the origin and point 25: 7235:, second edition, Springer, 2005. 7217:Escher's Circle Limit Exploration 6518:Relation to the hyperboloid model 6356:) in the halfplane model maps to 4467:{\displaystyle P=u\cdot (s-t)\,,} 213:be the radius of the sphere, and 7259: 7137:The Philosophy of Space and Time 7134:Reichenbach, Hans (2012-03-13). 6912:Circle Limit IV: Heaven and Hell 6841: 6764: 6091:The Poincaré disk model and the 5434:Relation to the Klein disk model 3110:in the boundary circle of point 2491:in the boundary circle of point 2223: 2040: 1815: 1713: 1594: 1550: 404:The hyperbolic distance between 7040:"Théorie des groupes fuchsiens" 5422:the Poincaré disk model (line 1224:, their hyperbolic distance is 1179:{\displaystyle x'=(r',\theta )} 1038:, the hyperbolic distance is: 6753:between a sphere and a plane. 6642: 6623: 6486: 6473: 6405: 6392: 6317: 6304: 6236: 6223: 5219: 5200: 5161: 5142: 5109: 5097: 5094: 5082: 5076: 5064: 5061: 5049: 5043: 5031: 5025: 5013: 4969: 4957: 4951: 4939: 4933: 4921: 4915: 4903: 4870: 4858: 4852: 4840: 4834: 4822: 4816: 4804: 4771: 4759: 4753: 4741: 4735: 4723: 4717: 4705: 4644: 4638: 4595: 4583: 4577: 4565: 4559: 4547: 4541: 4529: 4457: 4445: 4379: 4373: 4278: 4272: 4125: 4099: 4036: 4010: 3873: 3831: 3815: 3773: 3694: 3652: 3636: 3594: 2379: 2353: 2228: 2218: 2125:where the curvature matrix is 2045: 2035: 2023: 1997: 1820: 1810: 1719: 1708: 1347: 1318: 1211: 1199: 1173: 1156: 1004: 979: 976: 951: 840: 828: 799: 796: 784: 772: 756: 744: 678: 653: 650: 625: 589: 577: 436: 424: 62:, is a model of 2-dimensional 44:truncated triheptagonal tiling 1: 5809:{\displaystyle x^{2}+y^{2}=1} 5632:) in the Klein model maps to 5454:. The Klein disk model is an 5287:that intersects the boundary 4506:{\displaystyle Q=u\cdot u\,,} 1774:with dual coframe of 1-forms 1217:{\displaystyle x=(r,\theta )} 6187:) in the disk model maps to 5767:in the Poincaré disk model. 5488:in the Poincaré disk model. 4221:) are given by unit vectors 2235: 2052: 1955:. Solving this equation for 1827: 1604: 1560: 333:. Given two distinct points 329:Distances in this model are 27:Model of hyperbolic geometry 7249:, Jones and Bartlett, 1993. 7113:. Oxford University Press. 7038:Poincaré, H. (1882-12-01). 5853:{\displaystyle x=x\ ,\ y=y} 5250:In the Euclidean plane the 3152:be the midpoint of segment 2634:be the midpoint of segment 2410:By compass and straightedge 1132:inverse hyperbolic function 310:(hyperbolic) straight lines 266:{\displaystyle R^{2}-r^{2}} 42:Poincaré disk model of the 7308: 7282:Multi-dimensional geometry 6883: 6555:) on the hyperboloid and ( 6084: 5940:Conversely, from a vector 5448:The two models are related 5411: 1879: 556:-dimensional vector space 275:co-efficient of dilatation 6948:Poincaré half-plane model 6749:Compare the formulas for 6093:Poincaré half-plane model 5860:so the points are fixed. 3222:perpendicular to segment 2777:perpendicular to segment 147:is the similar model for 122:Poincaré half-space model 7090:Poincaré, Henri (1905). 6903:hyperbolic tessellations 6751:stereographic projection 6345:in the halfplane model. 5816:and the formulas become 5460:stereographic projection 5366:A blue horocycle in the 5310:of the boundary circle: 3427:A basic construction of 552:are two vectors in real 7247:The Poincaré Half-Plane 7140:. Courier Corporation. 6992:Penrose, Roger (2004). 6873:The (6,4,2) triangular 5456:orthographic projection 5260:great and small circles 4343:{\displaystyle \wedge } 1968:{\displaystyle \omega } 1903:{\displaystyle \omega } 7093:Science and hypothesis 6881: 6741: 6611: 6508: 6339: 6171: 6116: 6072: 5954: 5932: 5877: 5854: 5810: 5761: 5615: 5430: 5375: 5236: 5178: 5120: 4980: 4881: 4782: 4680: 4606: 4507: 4468: 4414: 4344: 4301: 4199: 3951: 3502: 3412: 3389: 3369: 3349: 3329: 3306: 3286: 3266: 3244: 3216: 3196: 3174: 3146: 3124: 3100: 3073: 3047: 3025: 2998: 2967: 2944: 2924: 2904: 2884: 2861: 2841: 2821: 2799: 2771: 2751: 2729: 2698: 2678: 2656: 2628: 2606: 2574: 2552: 2532: 2505: 2481: 2448: 2428: 2395: 2313: 2116: 1969: 1949: 1904: 1888:Levi-Civita connection 1866: 1765: 1640: 1415: 1388: 1357: 1218: 1180: 1124: 1104: 1021: 721: 692: 529: 311: 283: 267: 227: 207: 182:Science and Hypothesis 86:to the unit circle or 47: 35: 6872: 6865:Artistic realizations 6742: 6612: 6542:Cartesian coordinates 6526:, are related to the 6509: 6340: 6172: 6117: 6095:are both named after 6073: 5955: 5933: 5878: 5855: 5811: 5762: 5616: 5421: 5365: 5237: 5179: 5121: 4991:Binet–Cauchy identity 4981: 4882: 4783: 4681: 4607: 4508: 4469: 4415: 4345: 4302: 4200: 3952: 3503: 3413: 3390: 3370: 3350: 3330: 3307: 3287: 3267: 3245: 3217: 3197: 3175: 3147: 3125: 3101: 3074: 3048: 3026: 2999: 2968: 2945: 2925: 2905: 2885: 2862: 2842: 2822: 2800: 2772: 2752: 2730: 2699: 2679: 2657: 2629: 2607: 2575: 2553: 2533: 2506: 2482: 2449: 2429: 2405:Construction of lines 2396: 2314: 2117: 1970: 1950: 1905: 1867: 1766: 1641: 1412:icosahedral honeycomb 1405: 1389: 1358: 1219: 1181: 1125: 1105: 1022: 722: 693: 530: 306:Poincaré disk with 3 305: 268: 228: 208: 187: 124:, it was proposed by 41: 33: 7268:at Wikimedia Commons 7266:Poincaré disk models 6943:Beltrami–Klein model 6620: 6566: 6360: 6191: 6126: 6106: 5964: 5944: 5887: 5867: 5820: 5774: 5636: 5621:in the Klein model. 5503: 5269:A Euclidean circle: 5191: 5133: 5004: 4894: 4795: 4696: 4622: 4520: 4481: 4430: 4357: 4334: 4263: 3975: 3542: 3438: 3423:By analytic geometry 3402: 3379: 3359: 3339: 3319: 3296: 3276: 3256: 3226: 3206: 3186: 3156: 3136: 3114: 3085: 3060: 3037: 3033:Draw line m through 3012: 2988: 2957: 2934: 2914: 2894: 2874: 2851: 2831: 2811: 2781: 2761: 2741: 2711: 2688: 2668: 2638: 2618: 2588: 2564: 2542: 2517: 2495: 2466: 2438: 2418: 2329: 2240: 2132: 2057: 1982: 1959: 1918: 1894: 1832: 1781: 1668: 1609: 1565: 1429: 1398:Metric and curvature 1387:{\displaystyle r'=0} 1367: 1228: 1190: 1142: 1114: 1042: 734: 705: 571: 418: 331:Cayley–Klein metrics 237: 217: 197: 136:. It is named after 90:of the unit circle. 60:conformal disk model 7287:Hyperbolic geometry 7233:Hyperbolic Geometry 7231:James W. Anderson, 6938:Hyperbolic geometry 6728: 6679: 6514:in the disk model. 5368:Poincaré disk model 5252:generalized circles 3866: 3848: 3808: 3790: 3687: 3669: 3629: 3611: 3398:The part of circle 3243:{\displaystyle PP'} 3173:{\displaystyle PP'} 2953:The part of circle 2798:{\displaystyle QQ'} 2728:{\displaystyle PP'} 2655:{\displaystyle QQ'} 2605:{\displaystyle PP'} 2352: 2241: 2236: 2058: 2053: 1833: 1828: 1610: 1605: 1566: 1561: 1519: 1481: 562:isometric invariant 369:, that is, so that 145:Poincaré ball model 64:hyperbolic geometry 56:Poincaré disk model 7238:Eugenio Beltrami, 7057:10.1007/BF02592124 6968:Inversive geometry 6882: 6737: 6714: 6665: 6607: 6504: 6335: 6167: 6112: 6068: 5950: 5928: 5873: 5850: 5806: 5757: 5611: 5431: 5394:limiting parallels 5376: 5232: 5174: 5116: 4976: 4877: 4778: 4676: 4602: 4503: 4464: 4410: 4340: 4297: 4195: 3947: 3945: 3852: 3834: 3794: 3776: 3673: 3655: 3615: 3597: 3498: 3408: 3385: 3365: 3355:and going through 3345: 3325: 3302: 3282: 3262: 3240: 3212: 3192: 3170: 3142: 3120: 3099:{\displaystyle P'} 3096: 3072:{\displaystyle PQ} 3069: 3043: 3024:{\displaystyle PQ} 3021: 2994: 2963: 2940: 2920: 2910:and going through 2900: 2880: 2857: 2837: 2817: 2795: 2767: 2747: 2725: 2694: 2674: 2652: 2624: 2602: 2570: 2548: 2531:{\displaystyle Q'} 2528: 2501: 2480:{\displaystyle P'} 2477: 2444: 2424: 2391: 2338: 2309: 2300: 2112: 2103: 1965: 1945: 1900: 1862: 1761: 1636: 1505: 1504: 1467: 1463: 1416: 1384: 1353: 1214: 1176: 1136:hyperbolic tangent 1120: 1100: 1017: 1015: 717: 688: 525: 393:| > | 377:| > | 312: 298:Lines and distance 263: 223: 203: 134:Euclidean geometry 58:, also called the 48: 36: 7264:Media related to 7147:978-0-486-13803-9 7120:978-0-19-106526-2 6963:Hyperboloid model 6907:Circle Limit I–IV 6875:hyperbolic tiling 6851: 6731: 6605: 6528:hyperboloid model 6496: 6425: 6419: 6415: 6327: 6256: 6250: 6246: 6162: 6115:{\displaystyle u} 6063: 6041: 6005: 6002: 5953:{\displaystyle s} 5923: 5876:{\displaystyle u} 5840: 5834: 5770:For ideal points 5750: 5747: 5703: 5700: 5694: 5690: 5687: 5604: 5562: 5556: 5552: 5275:hyperbolic circle 4670: 4405: 4217:whose endpoints ( 4174: 4085: 3922: 3743: 3429:analytic geometry 3411:{\displaystyle c} 3388:{\displaystyle Q} 3368:{\displaystyle P} 3348:{\displaystyle C} 3328:{\displaystyle c} 3305:{\displaystyle n} 3285:{\displaystyle m} 3265:{\displaystyle C} 3215:{\displaystyle N} 3195:{\displaystyle n} 3145:{\displaystyle N} 3123:{\displaystyle P} 3046:{\displaystyle M} 2997:{\displaystyle M} 2966:{\displaystyle c} 2943:{\displaystyle Q} 2923:{\displaystyle P} 2903:{\displaystyle C} 2883:{\displaystyle c} 2860:{\displaystyle n} 2840:{\displaystyle m} 2820:{\displaystyle C} 2770:{\displaystyle N} 2750:{\displaystyle n} 2697:{\displaystyle M} 2677:{\displaystyle m} 2627:{\displaystyle N} 2573:{\displaystyle M} 2551:{\displaystyle Q} 2504:{\displaystyle P} 2447:{\displaystyle Q} 2427:{\displaystyle P} 2265: 2068: 1876:In two dimensions 1843: 1756: 1692: 1634: 1531: 1495: 1454: 1305: 1266: 1079: 1008: 1007: 947: 848: 847: 682: 544:Equivalently, if 539:natural logarithm 520: 226:{\displaystyle r} 206:{\displaystyle R} 16:(Redirected from 7299: 7263: 7219: 7214: 7208: 7207: 7205: 7203: 7193: 7187: 7186: 7173: 7167: 7166: 7158: 7152: 7151: 7131: 7125: 7124: 7104: 7098: 7097: 7087: 7078: 7077: 7059: 7044:Acta Mathematica 7035: 7029: 7022: 7016: 7015: 6999: 6989: 6918:Circle Limit III 6890:Circle Limit III 6853: 6852: 6835: 6824: 6798: 6791: 6768: 6746: 6744: 6743: 6738: 6732: 6730: 6729: 6727: 6722: 6702: 6698: 6697: 6696: 6680: 6678: 6673: 6649: 6641: 6640: 6616: 6614: 6613: 6608: 6606: 6604: 6593: 6592: 6583: 6578: 6577: 6513: 6511: 6510: 6505: 6502: 6498: 6497: 6495: 6494: 6493: 6469: 6468: 6458: 6451: 6450: 6438: 6437: 6427: 6423: 6417: 6416: 6414: 6413: 6412: 6388: 6387: 6377: 6369: 6344: 6342: 6341: 6336: 6333: 6329: 6328: 6326: 6325: 6324: 6300: 6299: 6289: 6288: 6287: 6275: 6274: 6258: 6254: 6248: 6247: 6245: 6244: 6243: 6219: 6218: 6208: 6200: 6176: 6174: 6173: 6168: 6163: 6161: 6147: 6136: 6121: 6119: 6118: 6113: 6077: 6075: 6074: 6069: 6064: 6062: 6051: 6047: 6043: 6042: 6025: 6011: 6006: 6004: 6003: 5986: 5974: 5959: 5957: 5956: 5951: 5937: 5935: 5934: 5929: 5924: 5922: 5905: 5897: 5882: 5880: 5879: 5874: 5859: 5857: 5856: 5851: 5838: 5832: 5815: 5813: 5812: 5807: 5799: 5798: 5786: 5785: 5766: 5764: 5763: 5758: 5756: 5752: 5751: 5749: 5748: 5746: 5745: 5733: 5732: 5717: 5705: 5701: 5698: 5692: 5691: 5689: 5688: 5686: 5685: 5673: 5672: 5657: 5645: 5620: 5618: 5617: 5612: 5610: 5606: 5605: 5603: 5602: 5601: 5589: 5588: 5572: 5564: 5560: 5554: 5553: 5551: 5550: 5549: 5537: 5536: 5520: 5512: 5452:hemisphere model 5440:Klein disk model 5241: 5239: 5238: 5233: 5227: 5226: 5183: 5181: 5180: 5175: 5169: 5168: 5125: 5123: 5122: 5117: 4985: 4983: 4982: 4977: 4886: 4884: 4883: 4878: 4787: 4785: 4784: 4779: 4685: 4683: 4682: 4677: 4671: 4669: 4661: 4660: 4651: 4634: 4633: 4611: 4609: 4608: 4603: 4512: 4510: 4509: 4504: 4473: 4471: 4470: 4465: 4419: 4417: 4416: 4411: 4406: 4404: 4396: 4395: 4386: 4369: 4368: 4349: 4347: 4346: 4341: 4306: 4304: 4303: 4298: 4204: 4202: 4201: 4196: 4175: 4173: 4172: 4171: 4162: 4161: 4149: 4148: 4139: 4138: 4128: 4124: 4123: 4111: 4110: 4094: 4086: 4084: 4083: 4082: 4073: 4072: 4060: 4059: 4050: 4049: 4039: 4035: 4034: 4022: 4021: 4005: 4000: 3999: 3987: 3986: 3956: 3954: 3953: 3948: 3946: 3923: 3921: 3920: 3919: 3910: 3909: 3897: 3896: 3887: 3886: 3876: 3865: 3860: 3847: 3842: 3830: 3829: 3807: 3802: 3789: 3784: 3772: 3771: 3761: 3756: 3751: 3744: 3742: 3741: 3740: 3731: 3730: 3718: 3717: 3708: 3707: 3697: 3686: 3681: 3668: 3663: 3651: 3650: 3628: 3623: 3610: 3605: 3593: 3592: 3582: 3577: 3571: 3570: 3558: 3557: 3507: 3505: 3504: 3499: 3463: 3462: 3450: 3449: 3417: 3415: 3414: 3409: 3394: 3392: 3391: 3386: 3374: 3372: 3371: 3366: 3354: 3352: 3351: 3346: 3334: 3332: 3331: 3326: 3311: 3309: 3308: 3303: 3291: 3289: 3288: 3283: 3271: 3269: 3268: 3263: 3249: 3247: 3246: 3241: 3239: 3221: 3219: 3218: 3213: 3201: 3199: 3198: 3193: 3179: 3177: 3176: 3171: 3169: 3151: 3149: 3148: 3143: 3129: 3127: 3126: 3121: 3105: 3103: 3102: 3097: 3095: 3078: 3076: 3075: 3070: 3052: 3050: 3049: 3044: 3030: 3028: 3027: 3022: 3003: 3001: 3000: 2995: 2980:Another way is: 2972: 2970: 2969: 2964: 2949: 2947: 2946: 2941: 2929: 2927: 2926: 2921: 2909: 2907: 2906: 2901: 2889: 2887: 2886: 2881: 2866: 2864: 2863: 2858: 2846: 2844: 2843: 2838: 2826: 2824: 2823: 2818: 2804: 2802: 2801: 2796: 2794: 2776: 2774: 2773: 2768: 2756: 2754: 2753: 2748: 2734: 2732: 2731: 2726: 2724: 2703: 2701: 2700: 2695: 2683: 2681: 2680: 2675: 2661: 2659: 2658: 2653: 2651: 2633: 2631: 2630: 2625: 2611: 2609: 2608: 2603: 2601: 2579: 2577: 2576: 2571: 2557: 2555: 2554: 2549: 2537: 2535: 2534: 2529: 2527: 2510: 2508: 2507: 2502: 2486: 2484: 2483: 2478: 2476: 2453: 2451: 2450: 2445: 2433: 2431: 2430: 2425: 2400: 2398: 2397: 2392: 2378: 2377: 2365: 2364: 2351: 2346: 2318: 2316: 2315: 2310: 2305: 2304: 2266: 2264: 2263: 2262: 2257: 2256: 2249: 2248: 2243: 2242: 2231: 2226: 2221: 2210: 2209: 2202: 2178: 2121: 2119: 2118: 2113: 2108: 2107: 2069: 2067: 2066: 2065: 2060: 2059: 2048: 2043: 2038: 2026: 1992: 1974: 1972: 1971: 1966: 1954: 1952: 1951: 1946: 1909: 1907: 1906: 1901: 1871: 1869: 1868: 1863: 1858: 1857: 1844: 1842: 1841: 1840: 1835: 1834: 1823: 1818: 1813: 1798: 1793: 1792: 1770: 1768: 1767: 1762: 1757: 1755: 1754: 1753: 1737: 1735: 1734: 1728: 1727: 1722: 1716: 1711: 1700: 1699: 1693: 1685: 1680: 1679: 1645: 1643: 1642: 1637: 1635: 1633: 1632: 1631: 1626: 1625: 1618: 1617: 1612: 1611: 1597: 1583: 1582: 1575: 1574: 1573: 1568: 1567: 1553: 1537: 1532: 1530: 1529: 1524: 1520: 1518: 1513: 1503: 1482: 1480: 1475: 1462: 1452: 1444: 1443: 1393: 1391: 1390: 1385: 1377: 1362: 1360: 1359: 1354: 1346: 1311: 1307: 1306: 1304: 1303: 1288: 1287: 1272: 1267: 1265: 1254: 1243: 1223: 1221: 1220: 1215: 1185: 1183: 1182: 1177: 1166: 1152: 1129: 1127: 1126: 1121: 1109: 1107: 1106: 1101: 1084: 1080: 1078: 1067: 1056: 1026: 1024: 1023: 1018: 1016: 1009: 1003: 1002: 975: 974: 950: 949: 948: 925: 924: 909: 908: 893: 872: 849: 843: 823: 822: 805: 726: 724: 723: 718: 697: 695: 694: 689: 683: 681: 677: 676: 649: 648: 623: 622: 621: 599: 534: 532: 531: 526: 521: 519: 518: 514: 501: 497: 484: 483: 479: 466: 462: 449: 400: 398: 392: 384: 382: 376: 292:Hans Reichenbach 272: 270: 269: 264: 262: 261: 249: 248: 232: 230: 229: 224: 212: 210: 209: 204: 177:Eugenio Beltrami 173:Bernhard Riemann 126:Eugenio Beltrami 112: 96: 21: 7307: 7306: 7302: 7301: 7300: 7298: 7297: 7296: 7272: 7271: 7256: 7228: 7226:Further reading 7223: 7222: 7215: 7211: 7201: 7199: 7195: 7194: 7190: 7185:. May 23, 2015. 7175: 7174: 7170: 7160: 7159: 7155: 7148: 7133: 7132: 7128: 7121: 7106: 7105: 7101: 7089: 7088: 7081: 7037: 7036: 7032: 7023: 7019: 7012: 6991: 6990: 6986: 6981: 6953:Poincaré metric 6934: 6924: 6892: 6867: 6862: 6861: 6860: 6857: 6854: 6842: 6837: 6830: 6822: 6815: 6804: 6793: 6789: 6782: 6772: 6769: 6756: 6703: 6688: 6654: 6650: 6632: 6618: 6617: 6594: 6584: 6569: 6564: 6563: 6560: 6553: 6520: 6485: 6460: 6459: 6442: 6429: 6428: 6404: 6379: 6378: 6370: 6367: 6363: 6358: 6357: 6316: 6291: 6290: 6279: 6266: 6259: 6235: 6210: 6209: 6201: 6198: 6194: 6189: 6188: 6148: 6137: 6124: 6123: 6104: 6103: 6089: 6083: 6052: 6017: 6013: 6012: 5978: 5962: 5961: 5942: 5941: 5906: 5898: 5885: 5884: 5865: 5864: 5818: 5817: 5790: 5777: 5772: 5771: 5737: 5724: 5709: 5677: 5664: 5649: 5643: 5639: 5634: 5633: 5593: 5580: 5573: 5565: 5541: 5528: 5521: 5513: 5510: 5506: 5501: 5500: 5436: 5416: 5410: 5384:(a curve whose 5360: 5338: 5324: 5293:hyperbolic line 5248: 5218: 5189: 5188: 5160: 5131: 5130: 5002: 5001: 4892: 4891: 4793: 4792: 4694: 4693: 4662: 4652: 4625: 4620: 4619: 4518: 4517: 4479: 4478: 4428: 4427: 4397: 4387: 4360: 4355: 4354: 4332: 4331: 4261: 4260: 4211: 4163: 4153: 4140: 4130: 4129: 4115: 4102: 4095: 4074: 4064: 4051: 4041: 4040: 4026: 4013: 4006: 3991: 3978: 3973: 3972: 3944: 3943: 3911: 3901: 3888: 3878: 3877: 3821: 3763: 3762: 3749: 3748: 3732: 3722: 3709: 3699: 3698: 3642: 3584: 3583: 3572: 3562: 3549: 3540: 3539: 3532: 3528: 3520: 3516: 3454: 3441: 3436: 3435: 3425: 3400: 3399: 3377: 3376: 3357: 3356: 3337: 3336: 3317: 3316: 3294: 3293: 3274: 3273: 3254: 3253: 3232: 3224: 3223: 3204: 3203: 3184: 3183: 3162: 3154: 3153: 3134: 3133: 3112: 3111: 3088: 3083: 3082: 3058: 3057: 3035: 3034: 3010: 3009: 2986: 2985: 2955: 2954: 2932: 2931: 2912: 2911: 2892: 2891: 2872: 2871: 2849: 2848: 2829: 2828: 2809: 2808: 2787: 2779: 2778: 2759: 2758: 2739: 2738: 2717: 2709: 2708: 2686: 2685: 2666: 2665: 2644: 2636: 2635: 2616: 2615: 2594: 2586: 2585: 2562: 2561: 2540: 2539: 2520: 2515: 2514: 2493: 2492: 2469: 2464: 2463: 2436: 2435: 2416: 2415: 2412: 2407: 2369: 2356: 2327: 2326: 2299: 2298: 2293: 2284: 2283: 2278: 2268: 2250: 2232: 2203: 2179: 2130: 2129: 2102: 2101: 2096: 2087: 2086: 2081: 2071: 2049: 2027: 1993: 1980: 1979: 1957: 1956: 1916: 1915: 1892: 1891: 1884: 1882:Poincaré metric 1878: 1849: 1824: 1802: 1784: 1779: 1778: 1745: 1741: 1717: 1671: 1666: 1665: 1657: 1619: 1601: 1576: 1557: 1538: 1488: 1484: 1483: 1453: 1435: 1427: 1426: 1418:The associated 1400: 1370: 1365: 1364: 1339: 1296: 1289: 1280: 1273: 1255: 1244: 1241: 1237: 1226: 1225: 1188: 1187: 1159: 1145: 1140: 1139: 1112: 1111: 1068: 1057: 1051: 1040: 1039: 1014: 1013: 994: 966: 916: 900: 873: 855: 851: 850: 824: 803: 802: 759: 732: 731: 703: 702: 668: 640: 624: 613: 600: 569: 568: 507: 503: 490: 486: 485: 472: 468: 455: 451: 450: 416: 415: 394: 388: 386: 378: 372: 370: 300: 253: 240: 235: 234: 215: 214: 195: 194: 169: 116:Along with the 102: 94: 70:are inside the 28: 23: 22: 15: 12: 11: 5: 7305: 7303: 7295: 7294: 7292:Henri Poincaré 7289: 7284: 7274: 7273: 7270: 7269: 7255: 7254:External links 7252: 7251: 7250: 7243: 7236: 7227: 7224: 7221: 7220: 7209: 7188: 7182:Stack Exchange 7168: 7153: 7146: 7126: 7119: 7099: 7079: 7030: 7017: 7010: 6983: 6982: 6980: 6977: 6976: 6975: 6970: 6965: 6960: 6955: 6950: 6945: 6940: 6933: 6930: 6899:H.S.M. Coxeter 6877:that inspired 6866: 6863: 6859: 6858: 6855: 6840: 6838: 6820: 6813: 6787: 6780: 6770: 6763: 6760: 6759: 6758: 6736: 6726: 6721: 6717: 6712: 6709: 6706: 6701: 6695: 6691: 6687: 6683: 6677: 6672: 6668: 6663: 6660: 6657: 6653: 6647: 6644: 6639: 6635: 6631: 6628: 6625: 6603: 6600: 6597: 6591: 6587: 6581: 6576: 6572: 6558: 6551: 6519: 6516: 6501: 6492: 6488: 6484: 6481: 6478: 6475: 6472: 6467: 6463: 6457: 6454: 6449: 6445: 6441: 6436: 6432: 6422: 6411: 6407: 6403: 6400: 6397: 6394: 6391: 6386: 6382: 6376: 6373: 6366: 6332: 6323: 6319: 6315: 6312: 6309: 6306: 6303: 6298: 6294: 6286: 6282: 6278: 6273: 6269: 6265: 6262: 6253: 6242: 6238: 6234: 6231: 6228: 6225: 6222: 6217: 6213: 6207: 6204: 6197: 6166: 6160: 6157: 6154: 6151: 6146: 6143: 6140: 6134: 6131: 6111: 6097:Henri Poincaré 6082: 6079: 6067: 6061: 6058: 6055: 6050: 6046: 6040: 6037: 6034: 6031: 6028: 6023: 6020: 6016: 6009: 6001: 5998: 5995: 5992: 5989: 5984: 5981: 5977: 5972: 5969: 5949: 5927: 5921: 5918: 5915: 5912: 5909: 5904: 5901: 5895: 5892: 5872: 5849: 5846: 5843: 5837: 5831: 5828: 5825: 5805: 5802: 5797: 5793: 5789: 5784: 5780: 5755: 5744: 5740: 5736: 5731: 5727: 5723: 5720: 5715: 5712: 5708: 5697: 5684: 5680: 5676: 5671: 5667: 5663: 5660: 5655: 5652: 5648: 5642: 5609: 5600: 5596: 5592: 5587: 5583: 5579: 5576: 5571: 5568: 5559: 5548: 5544: 5540: 5535: 5531: 5527: 5524: 5519: 5516: 5509: 5435: 5432: 5409: 5406: 5392:geodesics are 5359: 5356: 5337: 5334: 5323: 5320: 5319: 5318: 5315: 5304: 5303: 5296: 5285: 5278: 5247: 5244: 5243: 5242: 5231: 5225: 5221: 5217: 5214: 5211: 5208: 5205: 5202: 5199: 5196: 5185: 5184: 5173: 5167: 5163: 5159: 5156: 5153: 5150: 5147: 5144: 5141: 5138: 5127: 5126: 5115: 5111: 5108: 5105: 5102: 5099: 5096: 5093: 5090: 5087: 5084: 5081: 5078: 5075: 5072: 5069: 5066: 5063: 5060: 5057: 5054: 5051: 5048: 5045: 5042: 5039: 5036: 5033: 5030: 5027: 5024: 5021: 5018: 5015: 5012: 5009: 4987: 4986: 4975: 4971: 4968: 4965: 4962: 4959: 4956: 4953: 4950: 4947: 4944: 4941: 4938: 4935: 4932: 4929: 4926: 4923: 4920: 4917: 4914: 4911: 4908: 4905: 4902: 4899: 4888: 4887: 4876: 4872: 4869: 4866: 4863: 4860: 4857: 4854: 4851: 4848: 4845: 4842: 4839: 4836: 4833: 4830: 4827: 4824: 4821: 4818: 4815: 4812: 4809: 4806: 4803: 4800: 4789: 4788: 4777: 4773: 4770: 4767: 4764: 4761: 4758: 4755: 4752: 4749: 4746: 4743: 4740: 4737: 4734: 4731: 4728: 4725: 4722: 4719: 4716: 4713: 4710: 4707: 4704: 4701: 4687: 4686: 4675: 4668: 4665: 4659: 4655: 4649: 4646: 4643: 4640: 4637: 4632: 4628: 4613: 4612: 4601: 4597: 4594: 4591: 4588: 4585: 4582: 4579: 4576: 4573: 4570: 4567: 4564: 4561: 4558: 4555: 4552: 4549: 4546: 4543: 4540: 4537: 4534: 4531: 4528: 4525: 4514: 4513: 4502: 4498: 4495: 4492: 4489: 4486: 4475: 4474: 4463: 4459: 4456: 4453: 4450: 4447: 4444: 4441: 4438: 4435: 4421: 4420: 4409: 4403: 4400: 4394: 4390: 4384: 4381: 4378: 4375: 4372: 4367: 4363: 4339: 4308: 4307: 4296: 4292: 4289: 4286: 4283: 4280: 4277: 4274: 4271: 4268: 4210: 4207: 4206: 4205: 4194: 4190: 4187: 4184: 4181: 4178: 4170: 4166: 4160: 4156: 4152: 4147: 4143: 4137: 4133: 4127: 4122: 4118: 4114: 4109: 4105: 4101: 4098: 4092: 4089: 4081: 4077: 4071: 4067: 4063: 4058: 4054: 4048: 4044: 4038: 4033: 4029: 4025: 4020: 4016: 4012: 4009: 4003: 3998: 3994: 3990: 3985: 3981: 3960:If the points 3958: 3957: 3942: 3938: 3935: 3932: 3929: 3926: 3918: 3914: 3908: 3904: 3900: 3895: 3891: 3885: 3881: 3875: 3872: 3869: 3864: 3859: 3855: 3851: 3846: 3841: 3837: 3833: 3828: 3824: 3820: 3817: 3814: 3811: 3806: 3801: 3797: 3793: 3788: 3783: 3779: 3775: 3770: 3766: 3759: 3754: 3752: 3750: 3747: 3739: 3735: 3729: 3725: 3721: 3716: 3712: 3706: 3702: 3696: 3693: 3690: 3685: 3680: 3676: 3672: 3667: 3662: 3658: 3654: 3649: 3645: 3641: 3638: 3635: 3632: 3627: 3622: 3618: 3614: 3609: 3604: 3600: 3596: 3591: 3587: 3580: 3575: 3573: 3569: 3565: 3561: 3556: 3552: 3548: 3547: 3530: 3526: 3518: 3514: 3509: 3508: 3497: 3493: 3490: 3487: 3484: 3481: 3478: 3475: 3472: 3469: 3466: 3461: 3457: 3453: 3448: 3444: 3424: 3421: 3420: 3419: 3407: 3396: 3384: 3364: 3344: 3324: 3313: 3301: 3281: 3272:be where line 3261: 3250: 3238: 3235: 3231: 3211: 3191: 3180: 3168: 3165: 3161: 3141: 3130: 3119: 3094: 3091: 3079: 3068: 3065: 3042: 3031: 3020: 3017: 2993: 2975: 2974: 2962: 2951: 2939: 2919: 2899: 2879: 2868: 2856: 2836: 2827:be where line 2816: 2805: 2793: 2790: 2786: 2766: 2746: 2735: 2723: 2720: 2716: 2693: 2673: 2662: 2650: 2647: 2643: 2623: 2612: 2600: 2597: 2593: 2569: 2558: 2547: 2526: 2523: 2511: 2500: 2475: 2472: 2443: 2423: 2411: 2408: 2406: 2403: 2402: 2401: 2390: 2387: 2384: 2381: 2376: 2372: 2368: 2363: 2359: 2355: 2350: 2345: 2341: 2337: 2334: 2320: 2319: 2308: 2303: 2297: 2294: 2292: 2289: 2286: 2285: 2282: 2279: 2277: 2274: 2273: 2271: 2261: 2255: 2247: 2239: 2230: 2225: 2220: 2216: 2213: 2208: 2201: 2198: 2195: 2192: 2189: 2185: 2182: 2176: 2173: 2170: 2167: 2164: 2161: 2158: 2155: 2152: 2149: 2146: 2143: 2140: 2137: 2123: 2122: 2111: 2106: 2100: 2097: 2095: 2092: 2089: 2088: 2085: 2082: 2080: 2077: 2076: 2074: 2064: 2056: 2047: 2042: 2037: 2033: 2030: 2025: 2022: 2019: 2015: 2012: 2009: 2006: 2002: 1999: 1996: 1990: 1987: 1964: 1944: 1941: 1938: 1935: 1932: 1929: 1926: 1923: 1899: 1880:Main article: 1877: 1874: 1873: 1872: 1861: 1856: 1852: 1848: 1839: 1831: 1822: 1817: 1812: 1808: 1805: 1801: 1796: 1791: 1787: 1772: 1771: 1760: 1752: 1748: 1744: 1740: 1733: 1726: 1721: 1715: 1710: 1706: 1703: 1698: 1691: 1688: 1683: 1678: 1674: 1653: 1647: 1646: 1630: 1624: 1616: 1608: 1600: 1596: 1592: 1589: 1586: 1581: 1572: 1564: 1556: 1552: 1548: 1545: 1541: 1535: 1528: 1523: 1517: 1512: 1508: 1502: 1498: 1494: 1491: 1487: 1479: 1474: 1470: 1466: 1461: 1457: 1450: 1447: 1442: 1438: 1434: 1399: 1396: 1383: 1380: 1376: 1373: 1352: 1349: 1345: 1342: 1338: 1335: 1332: 1329: 1326: 1323: 1320: 1317: 1314: 1310: 1302: 1299: 1295: 1292: 1286: 1283: 1279: 1276: 1270: 1264: 1261: 1258: 1253: 1250: 1247: 1240: 1236: 1233: 1213: 1210: 1207: 1204: 1201: 1198: 1195: 1175: 1172: 1169: 1165: 1162: 1158: 1155: 1151: 1148: 1119: 1099: 1096: 1093: 1090: 1087: 1083: 1077: 1074: 1071: 1066: 1063: 1060: 1054: 1050: 1047: 1028: 1027: 1012: 1006: 1001: 997: 993: 990: 987: 984: 981: 978: 973: 969: 965: 962: 959: 956: 953: 946: 943: 940: 937: 934: 931: 928: 923: 919: 915: 912: 907: 903: 899: 896: 891: 888: 885: 882: 879: 876: 870: 867: 864: 861: 858: 856: 853: 852: 846: 842: 839: 836: 833: 830: 827: 820: 817: 814: 811: 808: 806: 804: 801: 798: 795: 792: 789: 786: 783: 780: 777: 774: 771: 768: 765: 762: 760: 758: 755: 752: 749: 746: 743: 740: 739: 716: 713: 710: 699: 698: 687: 680: 675: 671: 667: 664: 661: 658: 655: 652: 647: 643: 639: 636: 633: 630: 627: 620: 616: 612: 609: 606: 603: 597: 594: 591: 588: 585: 582: 579: 576: 524: 517: 513: 510: 506: 500: 496: 493: 489: 482: 478: 475: 471: 465: 461: 458: 454: 447: 444: 441: 438: 435: 432: 429: 426: 423: 316:straight lines 299: 296: 260: 256: 252: 247: 243: 222: 202: 168: 165: 138:Henri Poincaré 130:equiconsistent 101:by its center 76:straight lines 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 7304: 7293: 7290: 7288: 7285: 7283: 7280: 7279: 7277: 7267: 7262: 7258: 7257: 7253: 7248: 7244: 7241: 7237: 7234: 7230: 7229: 7225: 7218: 7213: 7210: 7198: 7192: 7189: 7184: 7183: 7178: 7172: 7169: 7164: 7157: 7154: 7149: 7143: 7139: 7138: 7130: 7127: 7122: 7116: 7112: 7111: 7103: 7100: 7095: 7094: 7086: 7084: 7080: 7075: 7071: 7067: 7063: 7058: 7053: 7049: 7046:(in French). 7045: 7041: 7034: 7031: 7028: 7021: 7018: 7013: 7011:0-224-04447-8 7007: 7003: 6998: 6997: 6988: 6985: 6978: 6974: 6971: 6969: 6966: 6964: 6961: 6959: 6956: 6954: 6951: 6949: 6946: 6944: 6941: 6939: 6936: 6935: 6931: 6929: 6927: 6922: 6920: 6919: 6914: 6913: 6908: 6904: 6900: 6896: 6891: 6887: 6880: 6876: 6871: 6864: 6839: 6833: 6828: 6819: 6812: 6808: 6802: 6796: 6786: 6779: 6775: 6767: 6762: 6757: 6754: 6752: 6747: 6734: 6724: 6719: 6715: 6710: 6707: 6704: 6699: 6693: 6689: 6685: 6681: 6675: 6670: 6666: 6661: 6658: 6655: 6651: 6645: 6637: 6633: 6629: 6626: 6601: 6598: 6595: 6589: 6585: 6579: 6574: 6570: 6561: 6554: 6547: 6543: 6538: 6536: 6532: 6529: 6525: 6517: 6515: 6499: 6490: 6482: 6479: 6476: 6470: 6465: 6461: 6455: 6452: 6447: 6443: 6439: 6434: 6430: 6420: 6409: 6401: 6398: 6395: 6389: 6384: 6380: 6374: 6371: 6364: 6355: 6351: 6346: 6330: 6321: 6313: 6310: 6307: 6301: 6296: 6292: 6284: 6280: 6276: 6271: 6267: 6263: 6260: 6251: 6240: 6232: 6229: 6226: 6220: 6215: 6211: 6205: 6202: 6195: 6186: 6182: 6177: 6164: 6158: 6155: 6152: 6149: 6144: 6141: 6138: 6132: 6129: 6109: 6100: 6098: 6094: 6088: 6080: 6078: 6065: 6059: 6056: 6053: 6048: 6044: 6038: 6035: 6032: 6029: 6026: 6021: 6018: 6014: 6007: 5999: 5996: 5993: 5990: 5987: 5982: 5979: 5975: 5970: 5967: 5947: 5938: 5925: 5919: 5916: 5913: 5910: 5907: 5902: 5899: 5893: 5890: 5870: 5861: 5847: 5844: 5841: 5835: 5829: 5826: 5823: 5803: 5800: 5795: 5791: 5787: 5782: 5778: 5768: 5753: 5742: 5738: 5734: 5729: 5725: 5721: 5718: 5713: 5710: 5706: 5695: 5682: 5678: 5674: 5669: 5665: 5661: 5658: 5653: 5650: 5646: 5640: 5631: 5627: 5622: 5607: 5598: 5594: 5590: 5585: 5581: 5577: 5574: 5569: 5566: 5557: 5546: 5542: 5538: 5533: 5529: 5525: 5522: 5517: 5514: 5507: 5498: 5494: 5489: 5487: 5483: 5479: 5474: 5472: 5468: 5463: 5461: 5457: 5453: 5449: 5445: 5441: 5433: 5429: 5425: 5420: 5415: 5407: 5405: 5401: 5399: 5395: 5391: 5390:perpendicular 5387: 5383: 5382: 5373: 5369: 5364: 5357: 5355: 5353: 5349: 5345: 5344: 5335: 5333: 5331: 5330: 5321: 5316: 5313: 5312: 5311: 5309: 5301: 5297: 5294: 5290: 5286: 5283: 5279: 5276: 5272: 5271: 5270: 5267: 5265: 5261: 5257: 5253: 5245: 5229: 5223: 5215: 5212: 5209: 5206: 5203: 5197: 5194: 5187: 5186: 5171: 5165: 5157: 5154: 5151: 5148: 5145: 5139: 5136: 5129: 5128: 5113: 5106: 5103: 5100: 5091: 5088: 5085: 5079: 5073: 5070: 5067: 5058: 5055: 5052: 5046: 5040: 5037: 5034: 5028: 5022: 5019: 5016: 5010: 5007: 5000: 4999: 4998: 4996: 4992: 4973: 4966: 4963: 4960: 4954: 4948: 4945: 4942: 4936: 4930: 4927: 4924: 4918: 4912: 4909: 4906: 4900: 4897: 4890: 4889: 4874: 4867: 4864: 4861: 4855: 4849: 4846: 4843: 4837: 4831: 4828: 4825: 4819: 4813: 4810: 4807: 4801: 4798: 4791: 4790: 4775: 4768: 4765: 4762: 4756: 4750: 4747: 4744: 4738: 4732: 4729: 4726: 4720: 4714: 4711: 4708: 4702: 4699: 4692: 4691: 4690: 4673: 4666: 4663: 4657: 4653: 4647: 4641: 4635: 4630: 4626: 4618: 4617: 4616: 4599: 4592: 4589: 4586: 4580: 4574: 4571: 4568: 4562: 4556: 4553: 4550: 4544: 4538: 4535: 4532: 4526: 4523: 4516: 4515: 4500: 4496: 4493: 4490: 4487: 4484: 4477: 4476: 4461: 4454: 4451: 4448: 4442: 4439: 4436: 4433: 4426: 4425: 4424: 4407: 4401: 4398: 4392: 4388: 4382: 4376: 4370: 4365: 4361: 4353: 4352: 4351: 4337: 4329: 4328:wedge product 4325: 4321: 4317: 4313: 4294: 4290: 4287: 4284: 4281: 4275: 4269: 4266: 4259: 4258: 4257: 4255: 4251: 4247: 4243: 4238: 4236: 4232: 4228: 4224: 4220: 4216: 4208: 4192: 4188: 4185: 4182: 4179: 4176: 4168: 4164: 4158: 4154: 4150: 4145: 4141: 4135: 4131: 4120: 4116: 4112: 4107: 4103: 4096: 4090: 4087: 4079: 4075: 4069: 4065: 4061: 4056: 4052: 4046: 4042: 4031: 4027: 4023: 4018: 4014: 4007: 4001: 3996: 3992: 3988: 3983: 3979: 3971: 3970: 3969: 3967: 3963: 3940: 3936: 3933: 3930: 3927: 3924: 3916: 3912: 3906: 3902: 3898: 3893: 3889: 3883: 3879: 3870: 3867: 3862: 3857: 3853: 3849: 3844: 3839: 3835: 3826: 3822: 3818: 3812: 3809: 3804: 3799: 3795: 3791: 3786: 3781: 3777: 3768: 3764: 3757: 3753: 3745: 3737: 3733: 3727: 3723: 3719: 3714: 3710: 3704: 3700: 3691: 3688: 3683: 3678: 3674: 3670: 3665: 3660: 3656: 3647: 3643: 3639: 3633: 3630: 3625: 3620: 3616: 3612: 3607: 3602: 3598: 3589: 3585: 3578: 3574: 3567: 3563: 3559: 3554: 3550: 3538: 3537: 3536: 3534: 3522: 3495: 3491: 3488: 3485: 3482: 3479: 3476: 3473: 3470: 3467: 3464: 3459: 3455: 3451: 3446: 3442: 3434: 3433: 3432: 3430: 3422: 3405: 3397: 3382: 3362: 3342: 3322: 3314: 3299: 3279: 3259: 3251: 3236: 3233: 3229: 3209: 3189: 3181: 3166: 3163: 3159: 3139: 3131: 3117: 3109: 3092: 3089: 3080: 3066: 3063: 3055: 3054:perpendicular 3040: 3032: 3018: 3015: 3007: 2991: 2983: 2982: 2981: 2978: 2960: 2952: 2937: 2917: 2897: 2877: 2869: 2854: 2834: 2814: 2806: 2791: 2788: 2784: 2764: 2744: 2736: 2721: 2718: 2714: 2706: 2705:perpendicular 2691: 2671: 2663: 2648: 2645: 2641: 2621: 2613: 2598: 2595: 2591: 2583: 2567: 2559: 2545: 2524: 2521: 2512: 2498: 2490: 2473: 2470: 2461: 2460: 2459: 2457: 2441: 2421: 2409: 2404: 2388: 2385: 2382: 2374: 2370: 2366: 2361: 2357: 2348: 2343: 2335: 2332: 2325: 2324: 2323: 2306: 2301: 2295: 2290: 2287: 2280: 2275: 2269: 2259: 2245: 2237: 2214: 2211: 2199: 2196: 2193: 2190: 2187: 2183: 2180: 2174: 2171: 2168: 2165: 2162: 2159: 2156: 2153: 2150: 2147: 2144: 2141: 2138: 2128: 2127: 2126: 2109: 2104: 2098: 2093: 2090: 2083: 2078: 2072: 2062: 2054: 2031: 2028: 2020: 2017: 2013: 2010: 2007: 2004: 2000: 1994: 1988: 1985: 1978: 1977: 1976: 1962: 1942: 1939: 1936: 1933: 1930: 1927: 1924: 1921: 1913: 1897: 1889: 1883: 1875: 1859: 1854: 1850: 1846: 1837: 1829: 1806: 1803: 1799: 1794: 1789: 1785: 1777: 1776: 1775: 1758: 1750: 1746: 1724: 1704: 1701: 1689: 1686: 1681: 1676: 1672: 1664: 1663: 1662: 1659: 1656: 1652: 1628: 1614: 1606: 1587: 1584: 1570: 1562: 1546: 1539: 1533: 1526: 1521: 1515: 1510: 1506: 1500: 1496: 1492: 1489: 1485: 1477: 1472: 1468: 1464: 1459: 1455: 1448: 1445: 1440: 1436: 1432: 1425: 1424: 1423: 1421: 1420:metric tensor 1413: 1409: 1404: 1397: 1395: 1381: 1378: 1374: 1371: 1350: 1343: 1340: 1336: 1333: 1330: 1327: 1324: 1321: 1315: 1312: 1308: 1300: 1297: 1293: 1290: 1284: 1281: 1277: 1274: 1268: 1262: 1259: 1256: 1251: 1248: 1245: 1238: 1234: 1231: 1208: 1205: 1202: 1196: 1193: 1170: 1167: 1163: 1160: 1153: 1149: 1146: 1137: 1133: 1117: 1097: 1094: 1091: 1088: 1085: 1081: 1075: 1072: 1069: 1064: 1061: 1058: 1052: 1048: 1045: 1037: 1032: 1010: 999: 991: 985: 982: 971: 963: 957: 954: 944: 941: 938: 935: 932: 929: 926: 921: 913: 905: 897: 889: 883: 880: 877: 868: 865: 862: 859: 857: 844: 837: 834: 831: 825: 818: 815: 812: 809: 807: 793: 790: 787: 781: 778: 775: 769: 766: 763: 761: 753: 750: 747: 741: 730: 729: 728: 711: 685: 673: 665: 659: 656: 645: 637: 631: 628: 618: 610: 607: 604: 595: 592: 586: 583: 580: 574: 567: 566: 565: 563: 559: 555: 551: 547: 542: 540: 535: 522: 515: 511: 508: 504: 498: 494: 491: 487: 480: 476: 473: 469: 463: 459: 456: 452: 445: 442: 439: 433: 430: 427: 421: 413: 411: 407: 402: 397: 391: 381: 375: 368: 364: 360: 356: 352: 348: 344: 340: 336: 332: 327: 325: 321: 317: 309: 308:ultraparallel 304: 297: 295: 293: 289: 288:Rudolf Carnap 282: 280: 276: 258: 254: 250: 245: 241: 220: 200: 192: 191:absolute zero 186: 184: 183: 178: 174: 166: 164: 162: 159:-dimensional 158: 154: 150: 146: 141: 139: 135: 131: 127: 123: 119: 114: 110: 106: 100: 91: 89: 85: 81: 80:circular arcs 77: 73: 69: 66:in which all 65: 61: 57: 53: 45: 40: 32: 19: 18:Poincaré disk 7246: 7245:Saul Stahl, 7239: 7232: 7212: 7200:. Retrieved 7191: 7180: 7171: 7162: 7156: 7136: 7129: 7109: 7102: 7092: 7047: 7043: 7033: 7026: 7020: 6995: 6987: 6958:Pseudosphere 6923: 6916: 6910: 6906: 6895:M. C. Escher 6893: 6886:M. C. Escher 6879:M. C. Escher 6831: 6817: 6810: 6806: 6803:viewed from 6794: 6784: 6777: 6773: 6755: 6748: 6556: 6549: 6545: 6539: 6534: 6531:projectively 6521: 6353: 6349: 6347: 6184: 6180: 6178: 6101: 6090: 5939: 5862: 5769: 5629: 5625: 5623: 5496: 5492: 5490: 5478:ideal points 5475: 5464: 5437: 5423: 5402: 5379: 5377: 5367: 5352:ideal points 5341: 5339: 5327: 5325: 5306:A Euclidean 5305: 5299: 5292: 5289:orthogonally 5281: 5274: 5268: 5263: 5249: 4988: 4688: 4614: 4422: 4323: 4319: 4315: 4311: 4309: 4253: 4249: 4245: 4241: 4239: 4234: 4230: 4226: 4222: 4219:ideal points 4218: 4215:circular arc 4212: 3965: 3961: 3959: 3524: 3512: 3510: 3426: 3335:with center 3315:Draw circle 2979: 2976: 2890:with center 2870:Draw circle 2413: 2321: 2124: 1885: 1773: 1660: 1654: 1650: 1648: 1417: 1035: 1033: 1029: 700: 557: 553: 549: 545: 543: 536: 414: 409: 405: 403: 395: 389: 379: 373: 366: 362: 358: 354: 350: 346: 343:ideal points 338: 334: 328: 315: 313: 284: 278: 188: 180: 170: 156: 152: 148: 144: 142: 115: 108: 104: 92: 59: 55: 49: 7202:13 December 7163:Geometry II 7050:(1): 1–62. 6524:Klein model 5398:ideal point 5372:ideal point 5348:right angle 5336:Hypercycles 5258:, they are 4995:dot product 3056:to segment 3008:of segment 2707:to segment 2584:of segment 2456:constructed 314:Hyperbolic 118:Klein model 78:are either 7276:Categories 6979:References 6926:HyperRogue 6884:See also: 6801:projection 6085:See also: 5412:See also: 5358:Horocycles 5343:hypercycle 5300:hypercycle 4989:Using the 3312:intersect. 3182:Draw line 2867:intersect. 2737:Draw line 2664:Draw line 1649:where the 1406:Poincaré ' 324:orthogonal 84:orthogonal 7074:120406828 7066:1871-2509 6827:unit disk 6711:∑ 6708:− 6662:∑ 6453:− 6348:A point ( 6311:− 6277:− 6264:− 6230:− 6179:A point ( 6057:⋅ 6036:⋅ 6030:− 6022:− 5997:⋅ 5991:− 5917:⋅ 5735:− 5722:− 5675:− 5662:− 5624:A point ( 5491:A point ( 5471:conformal 5381:horocycle 5282:horocycle 5213:⋅ 5207:− 5155:⋅ 5149:− 5104:⋅ 5089:⋅ 5080:− 5071:⋅ 5056:⋅ 5038:− 5029:⋅ 5020:− 4964:∧ 4955:⋅ 4946:∧ 4937:− 4928:− 4919:⋅ 4910:− 4865:∧ 4856:⋅ 4847:∧ 4838:− 4829:− 4820:⋅ 4811:− 4766:∧ 4757:⋅ 4748:∧ 4739:− 4730:− 4721:⋅ 4712:− 4642:θ 4636:⁡ 4590:∧ 4581:⋅ 4572:∧ 4563:− 4554:− 4545:⋅ 4536:− 4494:⋅ 4452:− 4443:⋅ 4377:θ 4371:⁡ 4338:∧ 4288:⋅ 4276:θ 4270:⁡ 4151:− 4113:− 4062:− 4024:− 3899:− 3819:− 3720:− 3640:− 3292:and line 3108:inversion 2847:and line 2489:inversion 2386:− 2340:Ω 2288:− 2215:− 2194:∧ 2181:− 2166:ω 2157:ω 2154:∧ 2151:ω 2145:ω 2136:Ω 2091:− 2032:− 2011:− 1986:ω 1963:ω 1943:θ 1940:∧ 1937:ω 1931:θ 1898:ω 1807:− 1786:θ 1743:∂ 1739:∂ 1705:− 1599:‖ 1591:‖ 1588:− 1555:‖ 1544:‖ 1497:∑ 1493:− 1456:∑ 1414:, {3,5,3} 1337:⁡ 1331:− 1325:⁡ 1278:− 1269:⋅ 1260:− 1235:⁡ 1209:θ 1171:θ 1095:⁡ 1073:− 1049:⁡ 996:‖ 989:‖ 986:− 968:‖ 961:‖ 958:− 936:⋅ 927:− 918:‖ 911:‖ 902:‖ 895:‖ 887:‖ 881:− 875:‖ 869:⁡ 826:δ 819:⁡ 782:δ 770:⁡ 715:‖ 712:⋅ 709:‖ 670:‖ 663:‖ 660:− 642:‖ 635:‖ 632:− 615:‖ 608:− 602:‖ 575:δ 446:⁡ 320:geodesics 251:− 161:unit ball 88:diameters 72:unit disk 6932:See also 4318:but not 3237:′ 3202:through 3167:′ 3093:′ 3006:midpoint 2792:′ 2757:through 2722:′ 2684:through 2649:′ 2599:′ 2582:midpoint 2525:′ 2474:′ 1910:that is 1375:′ 1344:′ 1301:′ 1285:′ 1164:′ 1150:′ 412:is then 120:and the 95:PSU(1,1) 52:geometry 6548:,  5322:Circles 3106:be the 3004:be the 2580:be the 2487:be the 1975:yields 1912:torsion 1134:of the 1130:is the 290:and of 167:History 99:SU(1,1) 7144:  7117:  7072:  7064:  7008:  6809:= −1, 6797:> 1 6424:  6418:  6255:  6249:  5839:  5833:  5702:  5699:  5693:  5561:  5555:  5467:chords 5428:models 5386:normal 5329:circle 5264:cycles 5256:sphere 5246:Cycles 4689:where 4423:where 4209:Angles 3525:v = (v 3513:u = (u 1334:artanh 1322:artanh 1118:artanh 1110:where 1092:artanh 816:arsinh 767:arcosh 701:where 399:| 387:| 383:| 371:| 74:, and 68:points 54:, the 7070:S2CID 6816:= 0, 5308:chord 5295:; and 5291:is a 4997:, as 3375:(and 2930:(and 132:with 7204:2015 7142:ISBN 7115:ISBN 7062:ISSN 7006:ISBN 6888:and 6823:= 0) 6540:For 5482:pole 5444:disk 5438:The 4248:and 4233:and 4225:and 3964:and 3523:and 3252:let 3132:let 3081:let 2984:let 2807:let 2614:let 2560:let 2513:let 2462:let 2458:by: 2434:and 1408:ball 548:and 408:and 385:and 349:and 337:and 143:The 7052:doi 6834:= 0 6829:at 6790:+ 1 6102:If 5863:If 5486:arc 5446:. 5388:or 4627:cos 4362:cos 4350:), 4322:= − 4314:= − 4310:If 4267:cos 4252:= − 4244:= − 564:by 318:or 151:or 107:, − 50:In 7278:: 7179:. 7082:^ 7068:. 7060:. 7042:. 7004:. 7002:45 6921:. 6792:, 6783:+ 6776:= 6099:. 5462:. 5378:A 5340:A 5326:A 3529:,v 3517:,u 3395:). 2950:). 2389:1. 1394:. 1232:ln 1046:ln 866:ln 541:. 443:ln 401:. 396:qb 390:pb 380:ap 374:aq 365:, 361:, 357:, 345:, 294:. 163:. 113:. 7206:. 7150:. 7123:. 7076:. 7054:: 7048:1 7014:. 6832:t 6821:2 6818:x 6814:1 6811:x 6807:t 6805:( 6795:t 6788:2 6785:x 6781:1 6778:x 6774:t 6735:. 6725:2 6720:i 6716:y 6705:1 6700:) 6694:i 6690:y 6686:2 6682:, 6676:2 6671:i 6667:y 6659:+ 6656:1 6652:( 6646:= 6643:) 6638:i 6634:x 6630:, 6627:t 6624:( 6602:t 6599:+ 6596:1 6590:i 6586:x 6580:= 6575:i 6571:y 6559:i 6557:y 6552:i 6550:x 6546:t 6544:( 6535:t 6500:) 6491:2 6487:) 6483:y 6480:+ 6477:1 6474:( 6471:+ 6466:2 6462:x 6456:1 6448:2 6444:y 6440:+ 6435:2 6431:x 6421:, 6410:2 6406:) 6402:y 6399:+ 6396:1 6393:( 6390:+ 6385:2 6381:x 6375:x 6372:2 6365:( 6354:y 6352:, 6350:x 6331:) 6322:2 6318:) 6314:y 6308:1 6305:( 6302:+ 6297:2 6293:x 6285:2 6281:y 6272:2 6268:x 6261:1 6252:, 6241:2 6237:) 6233:y 6227:1 6224:( 6221:+ 6216:2 6212:x 6206:x 6203:2 6196:( 6185:y 6183:, 6181:x 6165:. 6159:1 6156:+ 6153:u 6150:i 6145:i 6142:+ 6139:u 6133:= 6130:s 6110:u 6066:. 6060:s 6054:s 6049:s 6045:) 6039:s 6033:s 6027:1 6019:1 6015:( 6008:= 6000:s 5994:s 5988:1 5983:+ 5980:1 5976:s 5971:= 5968:u 5948:s 5926:. 5920:u 5914:u 5911:+ 5908:1 5903:u 5900:2 5894:= 5891:s 5871:u 5848:y 5845:= 5842:y 5836:, 5830:x 5827:= 5824:x 5804:1 5801:= 5796:2 5792:y 5788:+ 5783:2 5779:x 5754:) 5743:2 5739:y 5730:2 5726:x 5719:1 5714:+ 5711:1 5707:y 5696:, 5683:2 5679:y 5670:2 5666:x 5659:1 5654:+ 5651:1 5647:x 5641:( 5630:y 5628:, 5626:x 5608:) 5599:2 5595:y 5591:+ 5586:2 5582:x 5578:+ 5575:1 5570:y 5567:2 5558:, 5547:2 5543:y 5539:+ 5534:2 5530:x 5526:+ 5523:1 5518:x 5515:2 5508:( 5497:y 5495:, 5493:x 5424:P 5374:. 5302:. 5284:; 5277:; 5230:. 5224:2 5220:) 5216:t 5210:s 5204:1 5201:( 5198:= 5195:R 5172:, 5166:2 5162:) 5158:v 5152:u 5146:1 5143:( 5140:= 5137:Q 5114:. 5110:) 5107:t 5101:v 5098:( 5095:) 5092:s 5086:u 5083:( 5077:) 5074:s 5068:v 5065:( 5062:) 5059:t 5053:u 5050:( 5047:+ 5044:) 5041:t 5035:s 5032:( 5026:) 5023:v 5017:u 5014:( 5011:= 5008:P 4974:. 4970:) 4967:t 4961:s 4958:( 4952:) 4949:t 4943:s 4940:( 4934:) 4931:t 4925:s 4922:( 4916:) 4913:t 4907:s 4904:( 4901:= 4898:R 4875:, 4871:) 4868:v 4862:u 4859:( 4853:) 4850:v 4844:u 4841:( 4835:) 4832:v 4826:u 4823:( 4817:) 4814:v 4808:u 4805:( 4802:= 4799:Q 4776:, 4772:) 4769:t 4763:s 4760:( 4754:) 4751:v 4745:u 4742:( 4736:) 4733:t 4727:s 4724:( 4718:) 4715:v 4709:u 4706:( 4703:= 4700:P 4674:, 4667:R 4664:Q 4658:2 4654:P 4648:= 4645:) 4639:( 4631:2 4600:. 4596:) 4593:t 4587:s 4584:( 4578:) 4575:t 4569:s 4566:( 4560:) 4557:t 4551:s 4548:( 4542:) 4539:t 4533:s 4530:( 4527:= 4524:R 4501:, 4497:u 4491:u 4488:= 4485:Q 4462:, 4458:) 4455:t 4449:s 4446:( 4440:u 4437:= 4434:P 4408:, 4402:R 4399:Q 4393:2 4389:P 4383:= 4380:) 4374:( 4366:2 4330:( 4324:s 4320:t 4316:u 4312:v 4295:. 4291:s 4285:u 4282:= 4279:) 4273:( 4254:s 4250:t 4246:u 4242:v 4235:t 4231:s 4227:v 4223:u 4193:. 4189:0 4186:= 4183:1 4180:+ 4177:y 4169:1 4165:v 4159:2 4155:u 4146:2 4142:v 4136:1 4132:u 4126:) 4121:1 4117:u 4108:1 4104:v 4100:( 4097:2 4091:+ 4088:x 4080:1 4076:v 4070:2 4066:u 4057:2 4053:v 4047:1 4043:u 4037:) 4032:2 4028:v 4019:2 4015:u 4011:( 4008:2 4002:+ 3997:2 3993:y 3989:+ 3984:2 3980:x 3966:v 3962:u 3941:. 3937:0 3934:= 3931:1 3928:+ 3925:y 3917:1 3913:v 3907:2 3903:u 3894:2 3890:v 3884:1 3880:u 3874:) 3871:1 3868:+ 3863:2 3858:2 3854:v 3850:+ 3845:2 3840:1 3836:v 3832:( 3827:1 3823:u 3816:) 3813:1 3810:+ 3805:2 3800:2 3796:u 3792:+ 3787:2 3782:1 3778:u 3774:( 3769:1 3765:v 3758:+ 3746:x 3738:1 3734:v 3728:2 3724:u 3715:2 3711:v 3705:1 3701:u 3695:) 3692:1 3689:+ 3684:2 3679:2 3675:u 3671:+ 3666:2 3661:1 3657:u 3653:( 3648:2 3644:v 3637:) 3634:1 3631:+ 3626:2 3621:2 3617:v 3613:+ 3608:2 3603:1 3599:v 3595:( 3590:2 3586:u 3579:+ 3568:2 3564:y 3560:+ 3555:2 3551:x 3533:) 3531:2 3527:1 3521:) 3519:2 3515:1 3496:, 3492:0 3489:= 3486:1 3483:+ 3480:y 3477:b 3474:+ 3471:x 3468:a 3465:+ 3460:2 3456:y 3452:+ 3447:2 3443:x 3406:c 3383:Q 3363:P 3343:C 3323:c 3300:n 3280:m 3260:C 3234:P 3230:P 3210:N 3190:n 3164:P 3160:P 3140:N 3118:P 3090:P 3067:Q 3064:P 3041:M 3019:Q 3016:P 2992:M 2961:c 2938:Q 2918:P 2898:C 2878:c 2855:n 2835:m 2815:C 2789:Q 2785:Q 2765:N 2745:n 2719:P 2715:P 2692:M 2672:m 2646:Q 2642:Q 2622:N 2596:P 2592:P 2568:M 2546:Q 2522:Q 2499:P 2471:P 2442:Q 2422:P 2383:= 2380:) 2375:2 2371:e 2367:, 2362:1 2358:e 2354:( 2349:1 2344:2 2336:= 2333:K 2307:. 2302:) 2296:0 2291:1 2281:1 2276:0 2270:( 2260:2 2254:) 2246:2 2238:l 2229:| 2224:x 2219:| 2212:1 2207:( 2200:y 2197:d 2191:x 2188:d 2184:4 2175:= 2172:0 2169:+ 2163:d 2160:= 2148:+ 2142:d 2139:= 2110:, 2105:) 2099:0 2094:1 2084:1 2079:0 2073:( 2063:2 2055:l 2046:| 2041:x 2036:| 2029:1 2024:) 2021:y 2018:d 2014:x 2008:x 2005:d 2001:y 1998:( 1995:2 1989:= 1934:+ 1928:d 1925:= 1922:0 1860:. 1855:i 1851:x 1847:d 1838:2 1830:l 1821:| 1816:x 1811:| 1804:1 1800:2 1795:= 1790:i 1759:, 1751:i 1747:x 1732:) 1725:2 1720:| 1714:x 1709:| 1702:1 1697:( 1690:2 1687:1 1682:= 1677:i 1673:e 1655:i 1651:x 1629:2 1623:) 1615:2 1607:l 1595:x 1585:1 1580:( 1571:2 1563:l 1551:x 1547:d 1540:4 1534:= 1527:2 1522:) 1516:2 1511:i 1507:x 1501:i 1490:1 1486:( 1478:2 1473:i 1469:x 1465:d 1460:i 1449:4 1446:= 1441:2 1437:s 1433:d 1382:0 1379:= 1372:r 1351:. 1348:) 1341:r 1328:r 1319:( 1316:2 1313:= 1309:) 1298:r 1294:+ 1291:1 1282:r 1275:1 1263:r 1257:1 1252:r 1249:+ 1246:1 1239:( 1212:) 1206:, 1203:r 1200:( 1197:= 1194:x 1174:) 1168:, 1161:r 1157:( 1154:= 1147:x 1098:r 1089:2 1086:= 1082:) 1076:r 1070:1 1065:r 1062:+ 1059:1 1053:( 1036:r 1011:. 1005:) 1000:2 992:v 983:1 980:( 977:) 972:2 964:u 955:1 952:( 945:1 942:+ 939:v 933:u 930:2 922:2 914:v 906:2 898:u 890:+ 884:v 878:u 863:2 860:= 845:2 841:) 838:v 835:, 832:u 829:( 813:2 810:= 800:) 797:) 794:v 791:, 788:u 785:( 779:+ 776:1 773:( 764:= 757:) 754:v 751:, 748:u 745:( 742:d 686:, 679:) 674:2 666:v 657:1 654:( 651:) 646:2 638:u 629:1 626:( 619:2 611:v 605:u 596:2 593:= 590:) 587:v 584:, 581:u 578:( 558:R 554:n 550:v 546:u 523:. 516:| 512:b 509:q 505:| 499:| 495:p 492:a 488:| 481:| 477:b 474:p 470:| 464:| 460:q 457:a 453:| 440:= 437:) 434:q 431:, 428:p 425:( 422:d 410:q 406:p 367:b 363:q 359:p 355:a 351:b 347:a 339:q 335:p 259:2 255:r 246:2 242:R 221:r 201:R 157:n 153:n 149:3 111:} 109:I 105:I 103:{ 46:. 20:)

Index

Poincaré disk


truncated triheptagonal tiling
geometry
hyperbolic geometry
points
unit disk
straight lines
circular arcs
orthogonal
diameters
SU(1,1)
Klein model
Poincaré half-space model
Eugenio Beltrami
equiconsistent
Euclidean geometry
Henri Poincaré
unit ball
Bernhard Riemann
Eugenio Beltrami
Science and Hypothesis
absolute zero
co-efficient of dilatation
Rudolf Carnap
Hans Reichenbach

ultraparallel
geodesics

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