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Rook's graph

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2003: 546: 2491:. However, these cycles may involve moves between squares that are far apart within a single row or column of the chessboard. Instead, the study of "rook's tours", in the mathematics of chess, has generally concentrated on a special case of these Hamiltonian cycles where the rook is restricted to move only to adjacent squares. These single-step rook's tours only exist on boards with an even number of squares. They play a central role in the proof of 1288: 1900: 33: 2178: 2171: 2164: 2157: 2150: 2143: 2136: 2129: 2123: 2287:
largest independent set is equal to the number of cliques in a partition of the graph's vertices into a minimum number of cliques. In a rook's graph, the sets of rows or the sets of columns (whichever has fewer sets) form such an optimal partition. The size of the largest independent set in the graph is therefore
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Rook's graphs are highly symmetric, having symmetries taking every vertex to every other vertex. In rook's graphs defined from square chessboards, more strongly, every two edges are symmetric, and every pair of vertices is symmetric to every other pair at the same distance in moves (making the graph
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between any two squares sharing a row (rank) or column (file), the squares that a rook can move between. These graphs can be constructed for chessboards of any rectangular shape. Although rook's graphs have only minor significance in chess lore, they are more important in the abstract mathematics of
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of a rook's graph both equal the smaller of the chessboard's width and height. In terms of chess, the independence number is the maximum number of rooks that can be placed without attacking each other; the domination number is the minimum number needed to attack all unoccupied board squares. Rook's
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Any two vertices in a rook's graph are either at distance one or two from each other, according to whether they are adjacent or nonadjacent respectively. Any two nonadjacent vertices may be transformed into any other two nonadjacent vertices by a symmetry of the graph. When the rook's graph is not
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in a rook's graph is a set of vertices, no two of which belong to the same row or column of the graph; in chess terms, it corresponds to a placement of rooks no two of which attack each other. Perfect graphs may also be described as the graphs in which, in every induced subgraph, the size of the
1232:. These parameters describe the number of vertices, the number of edges per vertex, the number of triangles per edge, and the number of shared neighbors for two non-adjacent vertices, respectively. Conversely, every strongly regular graph with these parameters must be an 2017:
Because a rook's graph is perfect, the number of colors needed in any coloring of the graph is just the size of its largest clique. The cliques of a rook's graph are the subsets of a single row or a single column, and the largest of these have size
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of a graph is the minimum cardinality among all dominating sets. On the rook's graph a set of vertices is a dominating set if and only if their corresponding squares either occupy, or are a rook's move away from, all squares on the
1101:, these properties uniquely characterize the rook's graph. That is, the rook's graphs are the only graphs with these numbers of vertices, edges, triangles per edge, and with a unique 4-cycle through each two non-adjacent vertices. 1697:
of the symmetry group according to whether they are adjacent horizontally or vertically, but when the graph is square any two adjacent vertices may also be mapped into each other by a symmetry and the graph is therefore
1948:, and two vertices of the rook's graph are adjacent if and only if the corresponding edges of the complete bipartite graph share a common endpoint. In this view, an edge in the complete bipartite graph from the 1460:
rook's graph, the neighborhood of each vertex forms two triangles, one for its rank and another for its file, without any edges from one part of the neighborhood to the other. Another way of distinguishing the
1230: 1907:), colored with three colors and showing a clique of three vertices. In this graph and each of its induced subgraphs the chromatic number equals the clique number, so it is a perfect graph. 280:. With one exception, the rook's graphs can be distinguished from all other graphs using only two properties: the numbers of triangles each edge belongs to, and the existence of a unique 1846: 3527:
Burichenko, V. P.; Makhnev, A. A. (2011), "Об автоморфизмах сильно регулярных локально циклических графов" [On automorphisms of strongly regular locally cyclic graphs],
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so that no two squares in a row or column have the same color, using a number of colors equal to the maximum number of squares from the subset in any single row or column (the
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different values in such a way that the same value does not appear twice in any row or column. In the same way, a coloring of a rectangular rook's graph corresponds to a
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rook's graph. Other examples are known, and for some rook's graphs, a complete classification is known. For instance, there are two graphs whose neighborhoods are all
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to characterize the perfect graphs and to show that every graph with no odd hole and no odd antihole is perfect. In particular, rook's graphs are themselves perfect.
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that, if two squares of opposite colors are removed from a standard chessboard, the remaining squares can always be covered by dominoes. They are featured alongside
2783: 2557: 1099: 751: 534:. Its dimension as a Hamming graph is two, and every two-dimensional Hamming graph is a rook's graph for a square chessboard. Square rook's graphs are also called " 1628: 2751: 2609: 2583: 1654: 1515: 1349: 1282: 1128: 998: 972: 902: 803: 777: 4246:
Finite Geometries, Buildings, and Related Topics: Papers from the Conference on Buildings and Related Geometries held in Pingree Park, Colorado, July 17–23, 1988
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rook's graph can be covered by four cliques (the four ranks or the four files of the chessboard) whereas six cliques are needed to cover the Shrikhande graph.
3300: 1529:, meaning that they have symmetries taking every vertex to every other vertex. This implies that every vertex has an equal number of edges: they are 3558:. From the first page of the translation: "The Shrikhande graph is the only strongly regular locally hexagonal graph with parameters (16, 6, 2, 2)." 4309: 4299: 3202: 204: 3328: 2638:. There are only three classes of graphs (and finitely many exceptional graphs) that can have four eigenvalues with one of the four being 4201: 3917: 4165: 4074: 3448: 3411: 4031:
For an equivalent statement to the well-covered property of rook's graphs, in terms of matchings in complete bipartite graphs, see
4319: 1995:. Line graphs of bipartite graphs form an important family of perfect graphs: they are one of a small number of families used by 1886:, meaning that every isomorphism between two connected induced subgraphs can be extended to an automorphism of the whole graph. 3737: 3239: 2277:
A non-attacking placement of eight rooks on a chessboard, forming a maximum independent set in the corresponding rook's graph
3837: 3784: 3606: 3490: 2386:-tuple dominating set on the rook's graph is a set of vertices whose corresponding squares attack all other squares at least 2307: 2283: 1163: 4118:
Hurley, C. B.; Oldford, R. W. (February 2011), "Graphs as navigational infrastructure for high dimensional data spaces",
530:. Because the rook's graph for a square chessboard is the Cartesian product of equal-size cliques, it is an example of a 3995: 3845: 3841: 3200:
Azizoğlu, M. Cemil; Eğecioğlu, Ömer (2003), "Extremal sets minimizing dimension-normalized boundary in Hamming graphs",
2870: 2074:). Equivalently, it is NP-complete to determine whether a partial Latin square can be completed to a full Latin square. 1381:
rook's graph. The Shrikhande graph obeys the same properties listed by Moon and Moser. It can be distinguished from the
308: 2378:-dominating set is a set of vertices whose corresponding squares attack all other squares (via a rook's move) at least 1408: 508: 245: 1597:, the symmetries of the rook's graph are formed by independently permuting the rows and columns of the graph, so the 542:
are rook's graphs with some additional edges, connecting squares of a Sudoku puzzle that should have unequal values.
324:, meaning that placing non-attacking rooks one at a time can never get stuck until a set of maximum size is reached. 3773:
For the equivalence between Cartesian products of complete graphs and line graphs of complete bipartite graphs, see
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This follows from the definition of the rook's graph as a Cartesian product graph, together with Proposition 4 of
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to determine whether a partial coloring can be extended to a coloring of the whole graph (this problem is called
1699: 1571:. The rook's graphs are the only regular graphs formed from the moves of standard chess pieces in this way. When 269: 538:
graphs"; applied to a Latin square, its edges describe pairs of squares that cannot contain the same value. The
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Graph Theory and Combinatorics: Proceedings of the Cambridge Combinatorial Conference, in Honour of Paul Erdős
1795: 545: 307:). This class of induced subgraphs are a key component of a decomposition of perfect graphs used to prove the 489:
The squares of a single rank or file are all directly connected to each other, so each rank and file forms a
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The triangles within the rook's graph are formed by triples of squares within a single rank or file. When
3764:. See in particular Theorem 1, which identifies these graphs as line graphs of complete bipartite graphs. 2727:
rook's graph is spectrally unique: no other graph has the same spectrum. In particular this is true when
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embedded on a torus. This is not a rook's graph, but is strongly regular with the same parameters as the
3857: 3529: 2516: 2071: 1992: 1656:, the graph has additional symmetries that swap the rows and columns, so the number of automorphisms is 490: 236: 140: 43: 4033:
Lesk, M.; Plummer, M. D.; Pulleyblank, W. R. (1984), "Equi-matchable graphs", in Bollobás, Béla (ed.),
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Goethals, J.-M.; Seidel, J. J. (1970), "Strongly regular graphs derived from combinatorial designs",
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Matschke, Benjamin; Pfeifle, Julian; Pilaud, Vincent (2011), "Prodsimplicial-neighborly polytopes",
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rook's graph (or equivalently, as they describe it, the line graph of the complete bipartite graph
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Doob, Michael (1970), "On characterizing certain graphs with four eigenvalues by their spectra",
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For the equivalence between edge-coloring complete bipartite graphs and Latin squares, see e.g.
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chessboard. Its vertices represent the squares of the chessboard, and may be given coordinates
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of a complete bipartite graph, and correspondingly any line graph of a bipartite graph is an
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LeSaulnier, Timothy D.; Stocker, Christopher; Wenger, Paul S.; West, Douglas B. (2010),
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Geometrically, the rook's graphs can be formed by sets of the vertices and edges (the
4293: 4215: 4009: 3896: 3270: 3082: 2882: 1987:: in them, and in any of their induced subgraphs, the number of colors needed in any 1984: 1568: 531: 300: 292: 261: 184: 179: 4139: 4060: 4056: 3954:
Stones, Douglas S. (2010), "The many formulae for the number of Latin rectangles",
3597: 3367: 3288: 2661:; one of the three classes is the class of rook's graphs. For most combinations of 2066:. Although finding an optimal coloring of a rook's graph is straightforward, it is 2045: 2011: 2007: 1904: 1790: 1488: 578: 550: 539: 535: 225: 213: 4238: 3713: 3488:
Fiala, Nick C.; Haemers, Willem H. (2006), "5-chromatic strongly regular graphs",
3633:. See in particular equation (10), p. 748 for the automorphism group of the 3601: 3659:
rook's graph, and the discussion above the equation for the order of this group.
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th vertex on the other side corresponds to a chessboard square with coordinates
228: 4276: 3880: 3751: 3504: 1287: 4131: 3555: 3462: 3425: 3351: 3215: 2520: 1912: 566: 253: 232: 3085:, the graph of horizontal and vertical adjacencies of squares on a chessboard 4281: 3700:
Broere, Izak; Hattingh, Johannes H. (1990), "Products of circulant graphs",
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Gray, R.; Macpherson, D. (2010), "Countable connected-homogeneous graphs",
3620: 3253: 2413:-tuple domination number, respectively. On the square board, and for even 2310:
in a rook's graph can be extended to a maximum independent set, and every
470:, the vertices share a file and are connected by a vertical rook move; if 2499:
in the first work to discuss chess-piece tours, the 9th century Sanskrit
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of a rook's graph represents a square on a chessboard, and there is an
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graphs through their alternative constructions: rook's graphs are the
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Moore, Doug (1992), "Understanding simploids", in Kirk, David (ed.),
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is a four-dimensional shape formed as the Cartesian product of two
3342: 2001: 1898: 1286: 544: 486:, they share a rank and are connected by a horizontal rook move.) 3968: 3931: 3409:
Moon, J. W. (1963), "On the line-graph of the complete bigraph",
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chessboard can be formed from these two kinds of cliques, as the
4239:"Local recognition of graphs, buildings, and related geometries" 1996: 948:
edges (the ones connecting squares on the same file) belong to
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edges (the ones connecting squares on the same rank) belong to
3993:(1984), "The complexity of completing partial Latin squares", 1411:
of each vertex in the Shrikhande graph is connected to form a
1065:, namely the only rectangle using the two vertices as corners. 3446:(1964), "On the line graph of the complete bipartite graph", 295:. In other words, every subset of chessboard squares can be 4066:
Challenging Mathematical Problems with Elementary Solutions
2048:: it describes a way of filling the rows and columns of an 1983:
of a rook's graph. The line graphs of bipartite graphs are
4098:-tuple domination on the rook's graph and other results", 272:). For rectangular chessboards whose width and height are 260:. The square rook's graphs constitute the two-dimensional 1875:
vertices. Therefore, in this case, the rook's graph is a
1130:, these conditions may be abbreviated by stating that an 4154:
Across the Board: The Mathematics of Chessboard Problems
2030:, so this is also the chromatic number of the graph. An 4090:
Burchett, Paul; Lane, David; Lachniet, Jason (2009), "
3162:"The many formulae for the number of Latin rectangles" 1225:{\displaystyle \operatorname {srg} (n^{2},2n-2,n-2,2)} 915: 845: 3639: 3028: 2989: 2963: 2925: 2890: 2831: 2811: 2791: 2759: 2733: 2707: 2687: 2667: 2644: 2617: 2591: 2565: 2533: 1991:
is the same as the number of vertices in the largest
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square, the pairs of adjacent vertices fall into two
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Because these are all integers, rook's graphs are 167: 139: 119: 94: 82: 56: 42: 25: 3651: 3040: 3010: 2975: 2949: 2911: 2853: 2817: 2797: 2777: 2745: 2719: 2693: 2673: 2653: 2626: 2603: 2577: 2551: 1867: 1840: 1781: 1737: 1717: 1681: 1648: 1622: 1589: 1559: 1509: 1479: 1452: 1424: 1399: 1373: 1343: 1313: 1276: 1250: 1224: 1148: 1122: 1093: 1053: 1041:Every two nonadjacent vertices belong to a unique 1030: 992: 966: 940: 896: 870: 826: 797: 771: 745: 713: 687: 660: 627: 342:rook's graph represents the moves of a rook on an 2006:8-coloring of a chessboard graph obtained from a 2919:, for which the neighbors of each vertex form a 2083: 1952:th vertex on one side of the bipartition to the 1789:of the rook's graph contains as a subgroup the 1351:, there is another strongly regular graph, the 1933:— that is, it has one vertex for each edge of 311:, which characterizes all perfect graphs. The 288:connecting each nonadjacent pair of vertices. 3820: 3123:Journal of Statistical Planning and Inference 931: 918: 861: 848: 8: 4037:, London: Academic Press, pp. 239–254, 3301:Notices of the American Mathematical Society 2825:sum to at least 18 and do not have the form 1903:The 3×3 rook's graph (the graph of the 1487:rook's graph from the Shrikhande graph uses 3579:, Harvard University Mathematics Department 3577:Freshman Seminar 23j: Chess and Mathematics 2390:times and are themselves attacked at least 3293:"Sudoku squares and chromatic polynomials" 2983:rook's graphs: they are the Johnson graph 31: 4214: 4182:"The knight's tour: ancient and oriental" 4008: 3967: 3930: 3913:"Rainbow matching in edge-colored graphs" 3870: 3797: 3750: 3638: 3619: 3503: 3461: 3438: 3436: 3424: 3341: 3252: 3177: 3027: 2988: 2962: 2924: 2889: 2839: 2830: 2810: 2790: 2758: 2732: 2706: 2686: 2666: 2643: 2616: 2590: 2564: 2532: 2397:times. The minimum cardinality among all 1911:A rook's graph can also be viewed as the 1857: 1832: 1819: 1803: 1797: 1773: 1760: 1754: 1730: 1710: 1673: 1661: 1635: 1606: 1576: 1534: 1496: 1466: 1439: 1417: 1386: 1360: 1330: 1300: 1263: 1237: 1180: 1165: 1135: 1109: 1074: 1046: 1005: 979: 953: 930: 917: 914: 909: 883: 860: 847: 844: 839: 813: 784: 758: 726: 700: 677: 646: 640: 614: 328:Definition and mathematical constructions 4188:, vol. 22, no. 1, pp. 1–7 3155: 3153: 1841:{\displaystyle C_{mn}=C_{m}\times C_{n}} 3672:(1974), "The symmetry of line graphs", 3100: 721:chessboard. Each vertex is adjacent to 668:) has all of the following properties: 606: 224:that represents all legal moves of the 4156:, Princeton University Press, p.  3404: 3402: 22: 3483: 3481: 3329:Discrete & Computational Geometry 2314:in a rook's graph has the same size, 2177: 2170: 2163: 2156: 2149: 2142: 2135: 2128: 2119: 2044:rook's graph may be interpreted as a 695:vertices, one for each square of the 573:, the Cartesian products of pairs of 7: 3602:"On the number of bi-colored graphs" 3203:SIAM Journal on Discrete Mathematics 3112: 3110: 3108: 3106: 3104: 602: 4202:Linear Algebra and Its Applications 4063:(1987), "Solution to problem 34b", 3956:Electronic Journal of Combinatorics 3918:Electronic Journal of Combinatorics 3166:Electronic Journal of Combinatorics 2527:) consists of the four eigenvalues 422:are adjacent if and only if either 3850:"The strong perfect graph theorem" 3777:"On perfectness of sums of graphs" 3394:10.1016/b978-0-08-050755-2.50057-9 1355:, with the same parameters as the 1069:They show that except in the case 922: 852: 14: 4180:Murray, H. J. R. (January 1902), 3449:Annals of Mathematical Statistics 3412:Annals of Mathematical Statistics 1782:{\displaystyle S_{m}\times S_{n}} 941:{\displaystyle m{\tbinom {n}{2}}} 871:{\displaystyle n{\tbinom {m}{2}}} 779:squares on the same rank and the 3775:de Werra, D.; Hertz, A. (1999), 2877:a rook's graph have been called 2176: 2169: 2162: 2155: 2148: 2141: 2134: 2127: 2121: 497:. The whole rook's graph for an 493:—a subset of vertices forming a 386:. Two vertices with coordinates 3738:Journal of Combinatorial Theory 3240:Canadian Journal of Mathematics 2405:-tuple dominating sets are the 2359:board the domination number is 3607:Pacific Journal of Mathematics 3005: 2993: 2944: 2932: 2906: 2894: 2487:Every rook's graph contains a 1554: 1536: 1219: 1173: 589:rook's graph as its skeleton. 205:Table of graphs and parameters 1: 4310:Parametric families of graphs 4257:; see in particular pp. 89–90 3799:10.1016/S0012-365X(98)00168-X 3714:10.1080/16073606.1990.9631612 3136:10.1016/S0378-3758(98)00132-3 2950:{\displaystyle k\times (n-k)} 4216:10.1016/0024-3795(70)90037-6 4010:10.1016/0166-218X(84)90075-1 3996:Discrete Applied Mathematics 2457:-tuple domination number is 2453:. In a similar fashion, the 1852:by cyclically permuting the 753:edges, connecting it to the 561:rook's graph as its skeleton 309:strong perfect graph theorem 4300:Mathematical chess problems 3821:de Werra & Hertz (1999) 3160:Stones, Douglas S. (2010), 2854:{\displaystyle 2t^{2}\pm t} 2409:-domination number and the 509:Cartesian product of graphs 4336: 4186:The British Chess Magazine 3881:10.4007/annals.2006.164.51 3752:10.1016/j.jctb.2009.04.002 3505:10.1016/j.disc.2004.03.023 2785:, or when the two numbers 4152:Watkins, John J. (2004), 4132:10.1007/s00180-011-0228-6 3652:{\displaystyle n\times n} 3556:10.1134/S1064562411070076 3352:10.1007/s00454-010-9311-y 3216:10.1137/S0895480100375053 3041:{\displaystyle 4\times 4} 2976:{\displaystyle 3\times 3} 2869:The graphs for which the 2720:{\displaystyle m\times n} 1882:Square rook's graphs are 1480:{\displaystyle 4\times 4} 1453:{\displaystyle 4\times 4} 1407:rook's graph in that the 1400:{\displaystyle 4\times 4} 1374:{\displaystyle 4\times 4} 1314:{\displaystyle 4\times 4} 1251:{\displaystyle n\times n} 1149:{\displaystyle n\times n} 904:triangles; the remaining 805:squares on the same file. 714:{\displaystyle m\times n} 628:{\displaystyle m\times n} 258:complete bipartite graphs 203: 30: 18:Graph of chess rook moves 4237:Cohen, Arjeh M. (1990), 4120:Computational Statistics 3702:Quaestiones Mathematicae 1997:Chudnovsky et al. (2006) 1917:complete bipartite graph 276:, the rook's graphs are 4320:Strongly regular graphs 3573:"Graph theory glossary" 3550:84 (3): 778–782, 2011, 3463:10.1214/aoms/1177703593 3426:10.1214/aoms/1177704179 2881:. Examples include the 2519:of a rook's graph (the 2312:maximal independent set 1682:{\displaystyle 2n!^{2}} 1590:{\displaystyle m\neq n} 1560:{\displaystyle (m+n-2)} 1031:{\displaystyle m-2=n-2} 1000:, each edge belongs to 827:{\displaystyle m\neq n} 661:{\displaystyle K_{m,n}} 593:Regularity and symmetry 4100:Congressus Numerantium 3653: 3621:10.2140/pjm.1958.8.743 3254:10.4153/CJM-1970-067-9 3042: 3012: 3011:{\displaystyle J(6,3)} 2977: 2951: 2913: 2912:{\displaystyle J(n,k)} 2855: 2819: 2799: 2779: 2747: 2721: 2695: 2675: 2655: 2628: 2605: 2579: 2553: 2421:-domination number is 2374:On the rook's graph a 2014: 1908: 1869: 1842: 1783: 1739: 1719: 1683: 1650: 1624: 1591: 1561: 1511: 1481: 1454: 1434:. In contrast, in the 1426: 1401: 1375: 1345: 1322: 1315: 1278: 1252: 1226: 1158:strongly regular graph 1150: 1124: 1095: 1055: 1032: 994: 968: 942: 898: 872: 828: 799: 773: 747: 715: 689: 662: 629: 562: 4069:, Dover, p. 77, 3858:Annals of Mathematics 3654: 3530:Doklady Akademii Nauk 3043: 3013: 2978: 2952: 2914: 2856: 2820: 2800: 2780: 2778:{\displaystyle n=m-1} 2748: 2722: 2696: 2676: 2656: 2629: 2606: 2580: 2554: 2552:{\displaystyle m+n-2} 2472:is odd and less than 2072:precoloring extension 2005: 1902: 1884:connected-homogeneous 1870: 1843: 1784: 1749:, the symmetry group 1740: 1720: 1684: 1651: 1625: 1592: 1562: 1512: 1482: 1455: 1427: 1402: 1376: 1346: 1316: 1290: 1279: 1258:rook's graph, unless 1253: 1227: 1151: 1125: 1096: 1094:{\displaystyle m=n=4} 1056: 1033: 995: 969: 943: 899: 873: 829: 800: 774: 748: 746:{\displaystyle m+n-2} 716: 690: 663: 630: 553:, a four-dimensional 548: 3991:Colbourn, Charles J. 3785:Discrete Mathematics 3674:Utilitas Mathematica 3637: 3491:Discrete Mathematics 3388:, pp. 250–255, 3172:(1): Article 1, 46, 3067:independence complex 3026: 2987: 2961: 2923: 2888: 2829: 2809: 2789: 2757: 2731: 2705: 2685: 2665: 2642: 2615: 2589: 2563: 2531: 1856: 1796: 1753: 1729: 1709: 1660: 1634: 1623:{\displaystyle m!n!} 1605: 1575: 1533: 1495: 1465: 1438: 1416: 1385: 1359: 1329: 1299: 1262: 1236: 1164: 1134: 1108: 1073: 1045: 1004: 978: 952: 908: 882: 838: 812: 783: 757: 725: 699: 676: 639: 613: 577:. For instance, the 575:neighborly polytopes 162:− 2, −2} 3548:Doklady Mathematics 3069:of the rook's graph 2746:{\displaystyle n=2} 2604:{\displaystyle n-2} 2578:{\displaystyle m-2} 2304:well-covered graphs 1700:distance-transitive 1649:{\displaystyle m=n} 1510:{\displaystyle n=4} 1344:{\displaystyle n=4} 1277:{\displaystyle n=4} 1123:{\displaystyle m=n} 993:{\displaystyle m=n} 967:{\displaystyle n-2} 897:{\displaystyle m-2} 798:{\displaystyle n-1} 772:{\displaystyle m-1} 322:well-covered graphs 313:independence number 270:distance-transitive 4273:Weisstein, Eric W. 3649: 3285:Herzberg, Agnes M. 3063:Chessboard complex 3038: 3008: 2973: 2947: 2909: 2851: 2815: 2795: 2775: 2743: 2717: 2691: 2671: 2654:{\displaystyle -2} 2651: 2627:{\displaystyle -2} 2624: 2601: 2575: 2549: 2302:Rook's graphs are 2015: 1909: 1868:{\displaystyle mn} 1865: 1838: 1779: 1735: 1715: 1679: 1646: 1620: 1599:automorphism group 1587: 1557: 1525:Rook's graphs are 1507: 1477: 1450: 1422: 1397: 1371: 1341: 1323: 1311: 1274: 1248: 1222: 1156:rook's graph is a 1146: 1120: 1091: 1051: 1028: 990: 964: 938: 936: 894: 868: 866: 824: 795: 769: 743: 711: 688:{\displaystyle mn} 685: 658: 625: 563: 291:Rook's graphs are 3962:(1): A1:1–A1:46, 3925:(1): Note 26, 5, 3834:Chudnovsky, Maria 3498:(23): 3083–3096, 3382:Graphics Gems III 2818:{\displaystyle n} 2798:{\displaystyle m} 2694:{\displaystyle n} 2674:{\displaystyle m} 2489:Hamiltonian cycle 2336:domination number 2275: 2274: 1993:complete subgraph 1738:{\displaystyle n} 1718:{\displaystyle m} 1601:of the graph has 1527:vertex-transitive 1425:{\displaystyle 6} 1054:{\displaystyle 4} 929: 859: 609:observe that the 598:Strong regularity 569:) of a family of 317:domination number 246:Cartesian product 210: 209: 190:vertex-transitive 4327: 4286: 4285: 4258: 4256: 4243: 4234: 4228: 4227: 4218: 4196: 4190: 4189: 4177: 4171: 4170: 4149: 4143: 4142: 4115: 4109: 4107: 4097: 4094:-domination and 4093: 4087: 4081: 4079: 4053: 4047: 4045: 4029: 4023: 4021: 4012: 3987: 3981: 3980: 3971: 3951: 3945: 3943: 3934: 3907: 3901: 3899: 3874: 3854: 3830: 3824: 3818: 3812: 3810: 3801: 3781: 3771: 3765: 3763: 3754: 3732: 3726: 3724: 3696: 3690: 3688: 3666: 3660: 3658: 3656: 3655: 3650: 3632: 3623: 3594: 3588: 3586: 3585: 3584: 3565: 3559: 3546:. Translated in 3545: 3524: 3518: 3516: 3507: 3485: 3476: 3474: 3465: 3440: 3431: 3429: 3428: 3406: 3397: 3396: 3377: 3371: 3370: 3345: 3323: 3317: 3316: 3297: 3281: 3275: 3273: 3256: 3234: 3228: 3226: 3197: 3191: 3190: 3181: 3157: 3148: 3146: 3130:(1–2): 285–294, 3114: 3047: 3045: 3044: 3039: 3020:complement graph 3017: 3015: 3014: 3009: 2982: 2980: 2979: 2974: 2956: 2954: 2953: 2948: 2918: 2916: 2915: 2910: 2860: 2858: 2857: 2852: 2844: 2843: 2824: 2822: 2821: 2816: 2804: 2802: 2801: 2796: 2784: 2782: 2781: 2776: 2752: 2750: 2749: 2744: 2726: 2724: 2723: 2718: 2700: 2698: 2697: 2692: 2680: 2678: 2677: 2672: 2660: 2658: 2657: 2652: 2633: 2631: 2630: 2625: 2610: 2608: 2607: 2602: 2584: 2582: 2581: 2576: 2558: 2556: 2555: 2550: 2525:adjacency matrix 2493:Gomory's theorem 2478: 2471: 2467: 2456: 2452: 2442: 2427: 2420: 2416: 2412: 2408: 2404: 2401:-dominating and 2400: 2396: 2389: 2385: 2381: 2377: 2370: 2358: 2348: 2325: 2298: 2180: 2179: 2173: 2172: 2166: 2165: 2159: 2158: 2152: 2151: 2145: 2144: 2138: 2137: 2131: 2130: 2125: 2124: 2084: 2061: 2057: 2043: 2034:-coloring of an 2033: 2029: 1981:induced subgraph 1967: 1955: 1951: 1947: 1932: 1890:Other properties 1874: 1872: 1871: 1866: 1847: 1845: 1844: 1839: 1837: 1836: 1824: 1823: 1811: 1810: 1788: 1786: 1785: 1780: 1778: 1777: 1765: 1764: 1747:relatively prime 1744: 1742: 1741: 1736: 1724: 1722: 1721: 1716: 1688: 1686: 1685: 1680: 1678: 1677: 1655: 1653: 1652: 1647: 1629: 1627: 1626: 1621: 1596: 1594: 1593: 1588: 1566: 1564: 1563: 1558: 1516: 1514: 1513: 1508: 1486: 1484: 1483: 1478: 1459: 1457: 1456: 1451: 1433: 1431: 1429: 1428: 1423: 1406: 1404: 1403: 1398: 1380: 1378: 1377: 1372: 1353:Shrikhande graph 1350: 1348: 1347: 1342: 1320: 1318: 1317: 1312: 1293:Shrikhande graph 1283: 1281: 1280: 1275: 1257: 1255: 1254: 1249: 1231: 1229: 1228: 1223: 1185: 1184: 1160:with parameters 1155: 1153: 1152: 1147: 1129: 1127: 1126: 1121: 1100: 1098: 1097: 1092: 1060: 1058: 1057: 1052: 1037: 1035: 1034: 1029: 999: 997: 996: 991: 974:triangles. When 973: 971: 970: 965: 947: 945: 944: 939: 937: 935: 934: 921: 903: 901: 900: 895: 877: 875: 874: 869: 867: 865: 864: 851: 833: 831: 830: 825: 804: 802: 801: 796: 778: 776: 775: 770: 752: 750: 749: 744: 720: 718: 717: 712: 694: 692: 691: 686: 667: 665: 664: 659: 657: 656: 634: 632: 631: 626: 588: 571:convex polytopes 560: 529: 506: 485: 469: 453: 437: 421: 403: 385: 374: 363: 351: 341: 305:induced subgraph 283: 278:circulant graphs 274:relatively prime 222:undirected graph 163: 135: 121:Chromatic number 114: 102: 90: 78: 52: 37:8x8 Rook's graph 35: 23: 4335: 4334: 4330: 4329: 4328: 4326: 4325: 4324: 4290: 4289: 4271: 4270: 4267: 4262: 4261: 4241: 4236: 4235: 4231: 4198: 4197: 4193: 4179: 4178: 4174: 4168: 4151: 4150: 4146: 4117: 4116: 4112: 4095: 4091: 4089: 4088: 4084: 4077: 4055: 4054: 4050: 4032: 4030: 4026: 3989: 3988: 3984: 3953: 3952: 3948: 3910: 3908: 3904: 3852: 3838:Robertson, Neil 3832: 3831: 3827: 3819: 3815: 3792:(1–3): 93–101, 3779: 3774: 3772: 3768: 3734: 3733: 3729: 3699: 3697: 3693: 3668: 3667: 3663: 3635: 3634: 3596: 3595: 3591: 3582: 3580: 3567: 3566: 3562: 3526: 3525: 3521: 3487: 3486: 3479: 3442: 3441: 3434: 3408: 3407: 3400: 3379: 3378: 3374: 3325: 3324: 3320: 3295: 3283: 3282: 3278: 3236: 3235: 3231: 3199: 3198: 3194: 3159: 3158: 3151: 3116: 3115: 3102: 3097: 3054: 3024: 3023: 2985: 2984: 2959: 2958: 2921: 2920: 2886: 2885: 2873:of each vertex 2867: 2865:In other graphs 2835: 2827: 2826: 2807: 2806: 2787: 2786: 2755: 2754: 2729: 2728: 2703: 2702: 2683: 2682: 2663: 2662: 2640: 2639: 2636:integral graphs 2613: 2612: 2587: 2586: 2561: 2560: 2529: 2528: 2513: 2485: 2473: 2469: 2458: 2454: 2444: 2429: 2422: 2418: 2414: 2410: 2406: 2402: 2398: 2391: 2387: 2383: 2379: 2375: 2360: 2350: 2349:board. For the 2340: 2332: 2315: 2308:independent set 2288: 2284:independent set 2280: 2279: 2278: 2182: 2181: 2174: 2167: 2160: 2153: 2146: 2139: 2132: 2122: 2080: 2064:Latin rectangle 2059: 2049: 2035: 2031: 2019: 1989:vertex coloring 1973:bipartite graph 1957: 1953: 1949: 1946: 1934: 1931: 1919: 1897: 1892: 1877:circulant graph 1854: 1853: 1828: 1815: 1799: 1794: 1793: 1769: 1756: 1751: 1750: 1727: 1726: 1707: 1706: 1669: 1658: 1657: 1632: 1631: 1630:elements. When 1603: 1602: 1573: 1572: 1531: 1530: 1523: 1493: 1492: 1463: 1462: 1436: 1435: 1414: 1413: 1412: 1383: 1382: 1357: 1356: 1327: 1326: 1297: 1296: 1260: 1259: 1234: 1233: 1176: 1162: 1161: 1132: 1131: 1106: 1105: 1071: 1070: 1043: 1042: 1002: 1001: 976: 975: 950: 949: 916: 906: 905: 880: 879: 846: 836: 835: 810: 809: 781: 780: 755: 754: 723: 722: 697: 696: 674: 673: 642: 637: 636: 611: 610: 600: 595: 586: 558: 555:convex polytope 528: 519: 511: 498: 484: 477: 471: 468: 461: 455: 452: 445: 439: 436: 429: 423: 419: 412: 405: 401: 394: 387: 376: 365: 353: 343: 333: 330: 281: 250:complete graphs 199: 145: 125: 104: 100: 88: 62: 48: 38: 19: 12: 11: 5: 4333: 4331: 4323: 4322: 4317: 4315:Regular graphs 4312: 4307: 4305:Perfect graphs 4302: 4292: 4291: 4288: 4287: 4266: 4265:External links 4263: 4260: 4259: 4229: 4209:(4): 461–482, 4191: 4172: 4166: 4144: 4126:(4): 585–612, 4110: 4082: 4075: 4048: 4024: 3982: 3946: 3902: 3825: 3813: 3766: 3727: 3708:(2): 191–216, 3691: 3661: 3648: 3645: 3642: 3614:(4): 743–755, 3589: 3560: 3537:(2): 151–155, 3533:(in Russian), 3519: 3477: 3456:(2): 883–885, 3444:Hoffman, A. J. 3432: 3419:(2): 664–667, 3398: 3386:Academic Press 3372: 3336:(1): 100–131, 3318: 3308:(6): 708–717, 3276: 3247:(3): 597–614, 3229: 3210:(2): 219–236, 3192: 3149: 3099: 3098: 3096: 3093: 3092: 3091: 3086: 3080: 3078:Knight's graph 3075: 3070: 3060: 3058:Bishop's graph 3053: 3050: 3048:rook's graph. 3037: 3034: 3031: 3007: 3004: 3001: 2998: 2995: 2992: 2972: 2969: 2966: 2946: 2943: 2940: 2937: 2934: 2931: 2928: 2908: 2905: 2902: 2899: 2896: 2893: 2883:Johnson graphs 2866: 2863: 2850: 2847: 2842: 2838: 2834: 2814: 2794: 2774: 2771: 2768: 2765: 2762: 2742: 2739: 2736: 2716: 2713: 2710: 2690: 2670: 2650: 2647: 2623: 2620: 2600: 2597: 2594: 2574: 2571: 2568: 2548: 2545: 2542: 2539: 2536: 2512: 2509: 2497:knight's tours 2484: 2481: 2331: 2328: 2276: 2273: 2272: 2270: 2267: 2264: 2261: 2258: 2255: 2252: 2249: 2246: 2243: 2242: 2239: 2235: 2234: 2231: 2227: 2226: 2223: 2219: 2218: 2215: 2211: 2210: 2207: 2203: 2202: 2199: 2195: 2194: 2191: 2187: 2186: 2183: 2175: 2168: 2161: 2154: 2147: 2140: 2133: 2126: 2120: 2118: 2114: 2113: 2111: 2108: 2105: 2102: 2099: 2096: 2093: 2090: 2087: 2082: 2081: 2079: 2076: 1938: 1923: 1896: 1893: 1891: 1888: 1864: 1861: 1835: 1831: 1827: 1822: 1818: 1814: 1809: 1806: 1802: 1776: 1772: 1768: 1763: 1759: 1734: 1714: 1676: 1672: 1668: 1665: 1645: 1642: 1639: 1619: 1616: 1613: 1610: 1586: 1583: 1580: 1556: 1553: 1550: 1547: 1544: 1541: 1538: 1522: 1519: 1506: 1503: 1500: 1476: 1473: 1470: 1449: 1446: 1443: 1421: 1396: 1393: 1390: 1370: 1367: 1364: 1340: 1337: 1334: 1310: 1307: 1304: 1273: 1270: 1267: 1247: 1244: 1241: 1221: 1218: 1215: 1212: 1209: 1206: 1203: 1200: 1197: 1194: 1191: 1188: 1183: 1179: 1175: 1172: 1169: 1145: 1142: 1139: 1119: 1116: 1113: 1090: 1087: 1084: 1081: 1078: 1067: 1066: 1050: 1039: 1027: 1024: 1021: 1018: 1015: 1012: 1009: 989: 986: 983: 963: 960: 957: 933: 928: 925: 920: 913: 893: 890: 887: 863: 858: 855: 850: 843: 823: 820: 817: 806: 794: 791: 788: 768: 765: 762: 742: 739: 736: 733: 730: 710: 707: 704: 684: 681: 655: 652: 649: 645: 624: 621: 618: 607:Hoffman (1964) 599: 596: 594: 591: 524: 515: 495:complete graph 482: 475: 466: 459: 450: 443: 434: 427: 417: 410: 399: 392: 329: 326: 293:perfect graphs 262:Hamming graphs 252:, and are the 208: 207: 201: 200: 198: 197: 192: 187: 182: 177: 171: 169: 165: 164: 143: 137: 136: 123: 117: 116: 98: 92: 91: 86: 80: 79: 60: 54: 53: 46: 40: 39: 36: 28: 27: 17: 13: 10: 9: 6: 4: 3: 2: 4332: 4321: 4318: 4316: 4313: 4311: 4308: 4306: 4303: 4301: 4298: 4297: 4295: 4284: 4283: 4278: 4274: 4269: 4268: 4264: 4255: 4251: 4247: 4240: 4233: 4230: 4226: 4222: 4217: 4212: 4208: 4204: 4203: 4195: 4192: 4187: 4183: 4176: 4173: 4169: 4167:9780691130620 4163: 4159: 4155: 4148: 4145: 4141: 4137: 4133: 4129: 4125: 4121: 4114: 4111: 4105: 4101: 4086: 4083: 4078: 4076:9780486318578 4072: 4068: 4067: 4062: 4061:Yaglom, I. M. 4058: 4057:Yaglom, A. M. 4052: 4049: 4044: 4040: 4036: 4028: 4025: 4020: 4016: 4011: 4006: 4002: 3998: 3997: 3992: 3986: 3983: 3979: 3975: 3970: 3965: 3961: 3957: 3950: 3947: 3942: 3938: 3933: 3928: 3924: 3920: 3919: 3914: 3906: 3903: 3898: 3894: 3890: 3886: 3882: 3878: 3873: 3868: 3865:(1): 51–229, 3864: 3860: 3859: 3851: 3847: 3846:Thomas, Robin 3843: 3842:Seymour, Paul 3839: 3835: 3829: 3826: 3822: 3817: 3814: 3809: 3805: 3800: 3795: 3791: 3787: 3786: 3778: 3770: 3767: 3762: 3758: 3753: 3748: 3745:(2): 97–118, 3744: 3740: 3739: 3731: 3728: 3723: 3719: 3715: 3711: 3707: 3703: 3695: 3692: 3687: 3683: 3679: 3675: 3671: 3670:Biggs, Norman 3665: 3662: 3646: 3643: 3640: 3631: 3627: 3622: 3617: 3613: 3609: 3608: 3603: 3599: 3598:Harary, Frank 3593: 3590: 3578: 3574: 3571:(Fall 2004), 3570: 3564: 3561: 3557: 3553: 3549: 3544: 3540: 3536: 3532: 3531: 3523: 3520: 3515: 3511: 3506: 3501: 3497: 3493: 3492: 3484: 3482: 3478: 3473: 3469: 3464: 3459: 3455: 3451: 3450: 3445: 3439: 3437: 3433: 3427: 3422: 3418: 3414: 3413: 3405: 3403: 3399: 3395: 3391: 3387: 3383: 3376: 3373: 3369: 3365: 3361: 3357: 3353: 3349: 3344: 3339: 3335: 3331: 3330: 3322: 3319: 3315: 3311: 3307: 3303: 3302: 3294: 3290: 3289:Murty, M. Ram 3286: 3280: 3277: 3272: 3268: 3264: 3260: 3255: 3250: 3246: 3242: 3241: 3233: 3230: 3225: 3221: 3217: 3213: 3209: 3205: 3204: 3196: 3193: 3189: 3185: 3180: 3175: 3171: 3167: 3163: 3156: 3154: 3150: 3145: 3141: 3137: 3133: 3129: 3125: 3124: 3119: 3113: 3111: 3109: 3107: 3105: 3101: 3094: 3090: 3089:Queen's graph 3087: 3084: 3083:Lattice graph 3081: 3079: 3076: 3074: 3071: 3068: 3064: 3061: 3059: 3056: 3055: 3051: 3049: 3035: 3032: 3029: 3021: 3002: 2999: 2996: 2990: 2970: 2967: 2964: 2941: 2938: 2935: 2929: 2926: 2903: 2900: 2897: 2891: 2884: 2880: 2876: 2872: 2864: 2862: 2848: 2845: 2840: 2836: 2832: 2812: 2792: 2772: 2769: 2766: 2763: 2760: 2740: 2737: 2734: 2714: 2711: 2708: 2688: 2668: 2648: 2645: 2637: 2621: 2618: 2598: 2595: 2592: 2572: 2569: 2566: 2546: 2543: 2540: 2537: 2534: 2526: 2522: 2518: 2510: 2508: 2506: 2502: 2498: 2494: 2490: 2483:Hamiltonicity 2482: 2480: 2477: 2465: 2461: 2451: 2447: 2440: 2436: 2432: 2425: 2394: 2372: 2368: 2364: 2357: 2353: 2347: 2343: 2337: 2329: 2327: 2323: 2319: 2313: 2309: 2305: 2300: 2296: 2292: 2285: 2271: 2268: 2265: 2262: 2259: 2256: 2253: 2250: 2247: 2245: 2244: 2240: 2237: 2236: 2232: 2229: 2228: 2224: 2221: 2220: 2216: 2213: 2212: 2208: 2205: 2204: 2200: 2197: 2196: 2192: 2189: 2188: 2184: 2116: 2115: 2112: 2109: 2106: 2103: 2100: 2097: 2094: 2091: 2088: 2086: 2085: 2077: 2075: 2073: 2069: 2065: 2056: 2052: 2047: 2042: 2038: 2027: 2023: 2013: 2009: 2004: 2000: 1998: 1994: 1990: 1986: 1982: 1978: 1974: 1969: 1965: 1961: 1945: 1941: 1937: 1930: 1926: 1922: 1918: 1914: 1906: 1901: 1894: 1889: 1887: 1885: 1880: 1878: 1862: 1859: 1851: 1833: 1829: 1825: 1820: 1816: 1812: 1807: 1804: 1800: 1792: 1774: 1770: 1766: 1761: 1757: 1748: 1732: 1712: 1703: 1701: 1696: 1690: 1674: 1670: 1666: 1663: 1643: 1640: 1637: 1617: 1614: 1611: 1608: 1600: 1584: 1581: 1578: 1570: 1551: 1548: 1545: 1542: 1539: 1528: 1520: 1518: 1504: 1501: 1498: 1491:numbers: the 1490: 1474: 1471: 1468: 1447: 1444: 1441: 1419: 1410: 1394: 1391: 1388: 1368: 1365: 1362: 1354: 1338: 1335: 1332: 1321:rook's graph. 1308: 1305: 1302: 1294: 1289: 1285: 1271: 1268: 1265: 1245: 1242: 1239: 1216: 1213: 1210: 1207: 1204: 1201: 1198: 1195: 1192: 1189: 1186: 1181: 1177: 1170: 1167: 1159: 1143: 1140: 1137: 1117: 1114: 1111: 1102: 1088: 1085: 1082: 1079: 1076: 1064: 1048: 1040: 1025: 1022: 1019: 1016: 1013: 1010: 1007: 987: 984: 981: 961: 958: 955: 926: 923: 911: 891: 888: 885: 856: 853: 841: 821: 818: 815: 807: 792: 789: 786: 766: 763: 760: 740: 737: 734: 731: 728: 708: 705: 702: 682: 679: 671: 670: 669: 653: 650: 647: 643: 622: 619: 616: 608: 604: 597: 592: 590: 584: 580: 576: 572: 568: 556: 552: 547: 543: 541: 540:Sudoku graphs 537: 533: 532:Hamming graph 527: 523: 518: 514: 510: 505: 501: 496: 492: 487: 481: 474: 465: 458: 449: 442: 433: 426: 416: 409: 398: 391: 384: 380: 373: 369: 361: 357: 350: 346: 340: 336: 327: 325: 323: 318: 314: 310: 306: 302: 301:clique number 298: 294: 289: 287: 279: 275: 271: 265: 263: 259: 255: 251: 247: 242: 238: 234: 230: 227: 223: 219: 215: 206: 202: 196: 193: 191: 188: 186: 183: 181: 178: 176: 173: 172: 170: 166: 161: 157: 153: 149: 144: 142: 138: 133: 129: 124: 122: 118: 112: 108: 99: 97: 93: 87: 85: 81: 77: 73: 69: 65: 61: 59: 55: 51: 47: 45: 41: 34: 29: 24: 21: 16: 4280: 4277:"Rook Graph" 4245: 4232: 4206: 4200: 4194: 4185: 4175: 4153: 4147: 4123: 4119: 4113: 4103: 4099: 4085: 4065: 4051: 4034: 4027: 4003:(1): 25–30, 4000: 3994: 3985: 3969:10.37236/487 3959: 3955: 3949: 3932:10.37236/475 3922: 3916: 3905: 3872:math/0212070 3862: 3856: 3828: 3816: 3789: 3783: 3769: 3742: 3741:, Series B, 3736: 3730: 3705: 3701: 3694: 3677: 3673: 3664: 3611: 3605: 3592: 3581:, retrieved 3576: 3569:Elkies, Noam 3563: 3547: 3534: 3528: 3522: 3495: 3489: 3453: 3447: 3416: 3410: 3381: 3375: 3333: 3327: 3321: 3305: 3299: 3279: 3244: 3238: 3232: 3207: 3201: 3195: 3179:10.37236/487 3169: 3165: 3127: 3121: 3118:Laskar, Renu 3073:King's graph 2879:locally grid 2878: 2868: 2514: 2501:Kavyalankara 2500: 2486: 2475: 2463: 2459: 2449: 2445: 2438: 2434: 2430: 2423: 2392: 2373: 2366: 2362: 2355: 2351: 2345: 2341: 2333: 2321: 2317: 2301: 2294: 2290: 2281: 2078:Independence 2054: 2050: 2046:Latin square 2040: 2036: 2025: 2021: 2016: 2012:finite group 2008:Cayley table 1970: 1963: 1959: 1943: 1939: 1935: 1928: 1924: 1920: 1910: 1905:3-3 duoprism 1881: 1791:cyclic group 1704: 1691: 1524: 1489:clique cover 1409:neighborhood 1324: 1103: 1068: 601: 585:, and has a 579:3-3 duoprism 564: 551:3-3 duoprism 536:Latin square 525: 521: 516: 512: 503: 499: 488: 479: 472: 463: 456: 447: 440: 431: 424: 414: 407: 396: 389: 382: 378: 371: 367: 359: 355: 348: 344: 338: 334: 331: 290: 266: 218:rook's graph 217: 214:graph theory 211: 195:well-covered 159: 155: 151: 147: 131: 127: 110: 106: 75: 74:)/2 − 71: 67: 63: 49: 26:Rook's graph 20: 15: 3680:: 113–121, 2521:eigenvalues 2068:NP-complete 603:Moon (1963) 320:graphs are 254:line graphs 229:chess piece 158:− 2, 154:− 2, 4294:Categories 3583:2023-05-03 3095:References 3018:, and the 2330:Domination 2058:grid with 1913:line graph 1895:Perfection 1038:triangles. 834:, exactly 233:chessboard 168:Properties 4282:MathWorld 4106:: 187–204 3897:119151552 3644:× 3343:0908.4177 3271:199082328 3033:× 2968:× 2939:− 2930:× 2871:neighbors 2846:± 2770:− 2712:× 2646:− 2619:− 2596:− 2570:− 2544:− 2437:− 2 2395:− 1 2382:times. A 1826:× 1767:× 1582:≠ 1549:− 1472:× 1445:× 1392:× 1366:× 1306:× 1243:× 1208:− 1196:− 1171:⁡ 1141:× 1023:− 1011:− 959:− 889:− 819:≠ 790:− 764:− 738:− 706:× 620:× 583:triangles 567:skeletons 557:having a 4140:54220980 3889:20159988 3848:(2006), 3600:(1958), 3291:(2007), 3052:See also 2517:spectrum 2511:Spectrum 2306:: every 1977:subgraph 1521:Symmetry 1061:-vertex 364:, where 175:integral 141:Spectrum 84:Diameter 44:Vertices 4254:1072157 4225:0285432 4043:0777180 4019:0739595 3978:2661404 3941:2651735 3808:1663807 3761:2595694 3722:1068710 3686:0347684 3630:0103834 3543:2953786 3514:2273138 3472:0161328 3368:2070310 3360:2794360 3314:2327972 3263:0282872 3224:2032290 3188:2661404 3144:1673351 2523:of its 2505:Rudrata 2354:× 2344:× 2053:× 2039:× 1985:perfect 1569:regular 672:It has 303:of the 297:colored 248:of two 235:. Each 185:regular 180:perfect 4252:  4223:  4164:  4138:  4073:  4041:  4017:  3976:  3939:  3895:  3887:  3806:  3759:  3720:  3684:  3628:  3541:  3512:  3470:  3366:  3358:  3312:  3269:  3261:  3222:  3186:  3142:  3065:, the 2875:induce 2701:, the 2611:, and 2466:+ 1)/2 2448:< 2 2417:, the 1695:orbits 1432:-cycle 491:clique 454:. (If 237:vertex 220:is an 4242:(PDF) 4136:S2CID 3893:S2CID 3885:JSTOR 3867:arXiv 3853:(PDF) 3780:(PDF) 3364:S2CID 3338:arXiv 3296:(PDF) 3267:S2CID 3022:of a 2468:when 2428:when 2010:of a 1975:is a 1915:of a 1848:that 1705:When 1325:When 1104:When 1063:cycle 587:3 × 3 559:3 × 3 286:cycle 231:on a 113:) ≥ 3 96:Girth 58:Edges 4162:ISBN 4071:ISBN 2805:and 2681:and 2515:The 2443:and 2361:min( 2334:The 2316:min( 2289:min( 2020:max( 1971:Any 1850:acts 1745:are 1725:and 1291:The 605:and 549:The 404:and 377:1 ≤ 375:and 366:1 ≤ 315:and 241:edge 226:rook 216:, a 126:max( 105:max( 103:(if 4211:doi 4128:doi 4104:199 4005:doi 3964:doi 3927:doi 3877:doi 3863:164 3794:doi 3790:195 3747:doi 3743:100 3710:doi 3616:doi 3552:doi 3535:441 3500:doi 3496:306 3458:doi 3421:doi 3390:doi 3348:doi 3249:doi 3212:doi 3174:doi 3132:doi 2753:or 2503:of 2441:)/4 2433:≥ ( 2299:. 2282:An 1168:srg 438:or 332:An 256:of 212:In 4296:: 4279:, 4275:, 4250:MR 4221:MR 4219:, 4205:, 4184:, 4160:, 4158:12 4134:, 4124:26 4122:, 4102:, 4059:; 4039:MR 4015:MR 4013:, 3999:, 3974:MR 3972:, 3960:17 3958:, 3937:MR 3935:, 3923:17 3921:, 3915:, 3891:, 3883:, 3875:, 3861:, 3855:, 3844:; 3840:; 3836:; 3804:MR 3802:, 3788:, 3782:, 3757:MR 3755:, 3718:MR 3716:, 3706:13 3704:, 3682:MR 3676:, 3626:MR 3624:, 3610:, 3604:, 3575:, 3539:MR 3510:MR 3508:, 3494:, 3480:^ 3468:MR 3466:, 3454:35 3452:, 3435:^ 3417:34 3415:, 3401:^ 3384:, 3362:, 3356:MR 3354:, 3346:, 3334:46 3332:, 3310:MR 3306:54 3304:, 3298:, 3287:; 3265:, 3259:MR 3257:, 3245:22 3243:, 3220:MR 3218:, 3208:17 3206:, 3184:MR 3182:, 3170:17 3168:, 3164:, 3152:^ 3140:MR 3138:, 3128:76 3126:, 3103:^ 2861:. 2585:, 2559:, 2507:. 2479:. 2426:/2 2424:nk 2371:. 2365:, 2326:. 2320:, 2293:, 2024:, 1968:. 1962:, 1879:. 1702:. 1689:. 1284:. 520:◻ 502:× 478:= 462:= 446:= 430:= 413:, 395:, 381:≤ 370:≤ 358:, 347:× 337:× 264:. 150:+ 130:, 109:, 76:nm 70:+ 64:nm 50:nm 4213:: 4207:3 4130:: 4108:. 4096:k 4092:K 4080:. 4046:. 4022:. 4007:: 4001:8 3966:: 3944:. 3929:: 3900:. 3879:: 3869:: 3823:. 3811:. 3796:: 3749:: 3725:. 3712:: 3689:. 3678:5 3647:n 3641:n 3618:: 3612:8 3587:. 3554:: 3517:. 3502:: 3475:. 3460:: 3430:. 3423:: 3392:: 3350:: 3340:: 3274:. 3251:: 3227:. 3214:: 3176:: 3147:. 3134:: 3036:4 3030:4 3006:) 3003:3 3000:, 2997:6 2994:( 2991:J 2971:3 2965:3 2945:) 2942:k 2936:n 2933:( 2927:k 2907:) 2904:k 2901:, 2898:n 2895:( 2892:J 2849:t 2841:2 2837:t 2833:2 2813:n 2793:m 2773:1 2767:m 2764:= 2761:n 2741:2 2738:= 2735:n 2715:n 2709:m 2689:n 2669:m 2649:2 2622:2 2599:2 2593:n 2573:2 2567:m 2547:2 2541:n 2538:+ 2535:m 2476:n 2474:2 2470:k 2464:k 2462:( 2460:n 2455:k 2450:n 2446:k 2439:k 2435:k 2431:n 2419:k 2415:k 2411:k 2407:k 2403:k 2399:k 2393:k 2388:k 2384:k 2380:k 2376:k 2369:) 2367:n 2363:m 2356:n 2352:m 2346:n 2342:m 2324:) 2322:n 2318:m 2297:) 2295:n 2291:m 2269:h 2266:g 2263:f 2260:e 2257:d 2254:c 2251:b 2248:a 2241:1 2238:1 2233:2 2230:2 2225:3 2222:3 2217:4 2214:4 2209:5 2206:5 2201:6 2198:6 2193:7 2190:7 2185:8 2117:8 2110:h 2107:g 2104:f 2101:e 2098:d 2095:c 2092:b 2089:a 2060:n 2055:n 2051:n 2041:n 2037:n 2032:n 2028:) 2026:n 2022:m 1966:) 1964:j 1960:i 1958:( 1954:j 1950:i 1944:m 1942:, 1940:n 1936:K 1929:m 1927:, 1925:n 1921:K 1863:n 1860:m 1834:n 1830:C 1821:m 1817:C 1813:= 1808:n 1805:m 1801:C 1775:n 1771:S 1762:m 1758:S 1733:n 1713:m 1675:2 1671:! 1667:n 1664:2 1644:n 1641:= 1638:m 1618:! 1615:n 1612:! 1609:m 1585:n 1579:m 1567:- 1555:) 1552:2 1546:n 1543:+ 1540:m 1537:( 1505:4 1502:= 1499:n 1475:4 1469:4 1448:4 1442:4 1420:6 1395:4 1389:4 1369:4 1363:4 1339:4 1336:= 1333:n 1309:4 1303:4 1272:4 1269:= 1266:n 1246:n 1240:n 1220:) 1217:2 1214:, 1211:2 1205:n 1202:, 1199:2 1193:n 1190:2 1187:, 1182:2 1178:n 1174:( 1144:n 1138:n 1118:n 1115:= 1112:m 1089:4 1086:= 1083:n 1080:= 1077:m 1049:4 1026:2 1020:n 1017:= 1014:2 1008:m 988:n 985:= 982:m 962:2 956:n 932:) 927:2 924:n 919:( 912:m 892:2 886:m 862:) 857:2 854:m 849:( 842:n 822:n 816:m 793:1 787:n 767:1 761:m 741:2 735:n 732:+ 729:m 709:n 703:m 683:n 680:m 654:n 651:, 648:m 644:K 623:n 617:m 526:m 522:K 517:n 513:K 504:m 500:n 483:2 480:y 476:1 473:y 467:2 464:x 460:1 457:x 451:2 448:y 444:1 441:y 435:2 432:x 428:1 425:x 420:) 418:2 415:y 411:2 408:x 406:( 402:) 400:1 397:y 393:1 390:x 388:( 383:m 379:y 372:n 368:x 362:) 360:y 356:x 354:( 349:m 345:n 339:m 335:n 284:- 282:4 160:n 156:m 152:n 148:m 146:{ 134:) 132:m 128:n 115:) 111:m 107:n 101:3 89:2 72:m 68:n 66:(

Index


Vertices
Edges
Diameter
Girth
Chromatic number
Spectrum
integral
perfect
regular
vertex-transitive
well-covered
Table of graphs and parameters
graph theory
undirected graph
rook
chess piece
chessboard
vertex
edge
Cartesian product
complete graphs
line graphs
complete bipartite graphs
Hamming graphs
distance-transitive
relatively prime
circulant graphs
cycle
perfect graphs

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