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单词 Ramsey Number
释义

Ramsey Number

The Ramsey number gives the solution to the Party Problem, which asks the minimum number of guests that must be invited so that at least will know each other (i.e., there exists a Clique of order ) or at least will not know each other (i.e., there exists an independent set of order ). By symmetry, it is true that

(1)

It also must be true that
(2)

A generalized Ramsey number is written
(3)

and is the smallest Integer such that, no matter how each -element Subset of an -element Set iscolored with colors, there exists an such that there is a Subset of size , all of whose -elementSubsets are color . The usual Ramsey numbers are then equivalent to .


Bounds are given by

(4)

and
(5)

(Chung and Grinstead 1983). Erdös proved that for diagonal Ramsey numbers ,
(6)

This result was subsequently improved by a factor of 2 by Spencer (1975). was known since 1980 to be bounded fromabove by , and Griggs (1983) showed that was an acceptable limit. J.-H. Kim (Cipra 1995)subsequently bounded by a similar expression from below, so
(7)

Burr (1983) gives Ramsey numbers for all 113 graphs with no more than 6 Edges and no isolatedpoints.


A summary of known results up to 1983 for is given in Chung and Grinstead (1983). Radziszowski maintains anup-to-date list of the best current bounds, reproduced in part in the following table for .

Reference
336Greenwood and Gleason 1955
349Greenwood and Gleason 1955
3514Greenwood and Gleason 1955
3618Graver and Yackel 1968
3723Kalbfleisch 1966
3828McKay and Min 1992
3936Grinstead and Roberts 1982
310[40, 43]Exoo 1989, Radziszowski and Kreher 1988
311[46, 51]Radziszowski and Kreher 1988
312[52, 60]Exoo 1993, Radziszowski and Kreher 1988, Exoo 1998
313[60, 69]XZ, Radziszowski and Kreher 1988
314[66, 78]Exoo (unpub.), Radziszowski and Kreher 1988
315[73, 89]Wang and Wang 1989, Radziszowski (unpub.)
316[79, ]Wang and Wang 1989
317[92, ]WWY
318[98, ]WWY
319[106, ]WWY
320[109, ]WWY
321[122, ]WWY
322[125, ]WWY
323[136, ]WWY
4418Greenwood and Gleason 1955
4525Mckay and Radziszowski 1995
46[35, 41]Ex8, MR4
47[49, 62]
48[55, 85]Exoo 1998
49[69, 116]
410[80, 151]
411[93, 191]
412[98, 238]
413[112, 291]
414[119, 349]
415[128, 417]
55[43, 49]Ex4, MR4
56[58, 87]Exoo 1993, Walker 1971
57[80, 143]
58[95, 216]
59[116, 371]Exoo 1998
510[1, 445]
66[102, 165]Kalbfleisch 1965, Mac
67[109, 300]Exoo 1998
68[122, 497]Exoo 1998
69[153, 784]
610[167, 1180]
77[205, 545]Hill and Irving 1982, Giraud 1973
78[1, 1035]
79[1, 1724]
710[1, 2842]
88[282, 1874]
89[1, 3597]
810[1, 6116]
99[565, 6680]
910[1, 12795]
1010[798, 23981]Guldan and Tomasta ?
1111[522, ]Guldan and Tomasta ?


Known values for generalized Ramsey numbers are given in the following table.

BoundsReference
17Greenwood and Gleason 1955
[30, 32]
[45, 59]
Exoo 1998
[55, 81]
[128, 242]Hill and Irving 1982, Giraud 1973
[51, 64]Chung 1973, Sanchez-Flores 1995
[87, 159]Exoo 1998
[162, 317]
[1, 500]


Bounds
[14, 15]

See also Clique, Complete Graph,Extremal Graph, Irredundant Ramsey Number, Schur Number


References

Burr, S. A. ``Generalized Ramsey Theory for Graphs--A Survey.'' In Graphs and Combinatorics (Ed. R. A. Bari and F. Harary). New York: Springer-Verlag, pp. 52-75, 1964.

Burr, S. A. ``Diagonal Ramsey Numbers for Small Graphs.'' J. Graph Th. 7, 57-69, 1983.

Chartrand, G. ``The Problem of the Eccentric Hosts: An Introduction to Ramsey Numbers.'' §5.1 in Introductory Graph Theory. New York: Dover, pp. 108-115, 1985.

Chung, F. R. K. ``On the Ramsey Numbers .'' Discrete Math. 5, 317-321, 1973.

Chung, F. and Grinstead, C. G. ``A Survey of Bounds for Classical Ramsey Numbers.'' J. Graph. Th. 7, 25-37, 1983.

Cipra, B. ``A Visit to Asymptopia Yields Insights into Set Structures.'' Science 267, 964-965, 1995.

Exoo, G. ``On Two Classical Ramsey Numbers of the Form .'' SIAM J. Discrete Math. 2, 488-490, 1989.

Exoo, G. ``Announcement: On the Ramsey Numbers , and .'' Ars Combin. 35, 85, 1993.

Exoo, G. ``Some New Ramsey Colorings.'' Electronic J. Combinatorics 5, No. 1, R29, 1-5, 1998.http://www.combinatorics.org/Volume_5/v5i1toc.html.

Folkmann, J. ``Notes on the Ramsey Number .'' J. Combinat. Theory. Ser. A 16, 371-379, 1974.

Gardner, M. ``Mathematical Games: In Which Joining Sets of Points by Lines Leads into Diverse (and Diverting) Paths.'' Sci. Amer. 237, 18-28, 1977.

Gardner, M. Penrose Tiles and Trapdoor Ciphers... and the Return of Dr. Matrix, reissue ed. New York: W. H. Freeman, pp. 240-241, 1989.

Giraud, G. ``Une minoration du nombre de quadrangles unicolores et son application a la majoration des nombres de Ramsey binaires bicolors.'' C. R. Acad. Sci. Paris A 276, 1173-1175, 1973.

Graham, R. L.; Rothschild, B. L.; and Spencer, J. H. Ramsey Theory, 2nd ed. New York: Wiley, 1990.

Graver, J. E. and Yackel, J. ``Some Graph Theoretic Results Associated with Ramsey's Theorem.'' J. Combin. Th. 4, 125-175, 1968.

Greenwood, R. E. and Gleason, A. M. ``Combinatorial Relations and Chromatic Graphs.'' Canad. J. Math. 7, 1-7, 1955.

Griggs, J. R. ``An Upper Bound on the Ramsey Numbers .'' J. Comb. Th. A 35, 145-153, 1983.

Grinstead, C. M. and Roberts, S. M. ``On the Ramsey Numbers and .'' J. Combinat. Th. Ser. B 33, 27-51, 1982.

Guldan, F. and Tomasta, P. ``New Lower Bounds of Some Diagonal Ramsey Numbers.'' J. Graph. Th. 7, 149-151, 1983.

Hanson, D. ``Sum-Free Sets and Ramsey Numbers.'' Discrete Math. 14, 57-61, 1976.

Harary, F. ``Recent Results on Generalized Ramsey Theory for Graphs.'' Graph Theory and Applications (Ed. Y. Alai, D. R. Lick, and A. T. White). New York: Springer-Verlag, pp. 125-138, 1972.

Hill, R. and Irving, R. W. ``On Group Partitions Associated with Lower Bounds for Symmetric Ramsey Numbers.'' European J. Combin. 3, 35-50, 1982.

Kalbfleisch, J. G. Chromatic Graphs and Ramsey's Theorem. Ph.D. thesis, University of Waterloo, January 1966.

McKay, B. D. and Min, Z. K. ``The Value of the Ramsey Number .'' J. Graph Th. 16, 99-105, 1992.

McKay, B. D. and Radziszowski, S. P. ``.'' J. Graph. Th 19, 309-322, 1995.

Piwakowski, K. ``Applying Tabu Search to Determine New Ramsey Numbers.'' Electronic J. Combinatorics 3, R6 1-4, 1996.http://www.combinatorics.org/Volume_3/volume3.html#R6.

Radziszowski, S. P. ``Small Ramsey Numbers.'' Electronic J. Combin. 1, DS1 1-29, Rev. Mar. 25, 1996. http://ejc.math.gatech.edu:8080/Journal/Surveys/ds1.ps.

Radziszowski, S. and Kreher, D. L. ``Upper Bounds for Some Ramsey Numbers .'' J. Combinat. Math. Combin. Comput. 4, 207-212, 1988.

Spencer, J. H. ``Ramsey's Theorem--A New Lower Bound.'' J. Combinat. Theory Ser. A 18, 108-115, 1975.

Wang, Q. and Wang, G. ``New Lower Bounds for the Ramsey Numbers .'' Beijing Daxue Xuebao 25, 117-121, 1989.

Whitehead, E. G. ``The Ramsey Number .'' Discrete Math. 4, 389-396, 1973.

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