The conclusion is: in combinatorial mathematics, Ramsey theorem is to solve the following problem, and find such a minimum number n, so there must be K people who know each other or L people who don't know each other.

20 1 1 In May, 2008, a logic academic conference jointly organized by Peking University, Nanjing University and Zhejiang Normal University was held in Zhejiang Normal University. The report of Liu Jiayi, who loves mathematical logic in the School of Mathematical Science and Computing Technology of Central South University, gives a negative answer to this open question and completely solves the Sitapan conjecture.

Sitapan conjecture is a conjecture about the probative power of Ramsey's second coloring theorem put forward by British mathematical logician Sitapan in 1990s.

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Ramsey's Dichromatic Theorem is named after frank ramsey. The definition of Ramsey number has two descriptions in the language of graph theory: for all N-vertex graphs, there is a group of K vertices or an independent set of L vertices.

The smallest natural number n with this property is called Ramsey number, which is described in coloring theory. For any two-edge coloring (e 1, e2) of a complete graph Kn, Kn[e 1] should contain a k-order sub-complete graph, and Kn[e2] should contain an l-order sub-complete graph.

Ramsey proved that the solutions of given positive integers k and l, R(k, l) are unique and finite.