翟明清教授，滁州学院

Turán-type problem may be one of central problems in extremal graph theory. Particularly, the Turán number of a cycle attracts much attention. In this talk, we introduce a terminology, that is, theta graphs, which extends a one of cycles, We first give a brief survey on degenerated theta graphs. Then, we focus on the Turán number of θ(p,q,r), where p,q and r have different parities. This is a joint work with Longfei Fang and Jinlong Shu.