题目：Extremal results on multipartite graphs

报告人: Yi Zhao (Geogia State University)

时间：6月12号下午4：00-5：00 

地点：5106

摘要：Let K_r(t) denote the complete r-partite graph with t vertices in each part. Erdos and Simonovits (1971) characterized extremal graphs for K_r(t) when t\le 3. We obtain a multipartite version of this result by considering the maximum number of edges in a K_r(t)-free k-partite graph with n vertices in each part. We obtain an exact result whenever k=r, t\le 3, and n is sufficiently large, upper and lower bounds that differ O(n) in all cases. This is a joint work with Jie Han.