Title: Results and problems on partition of multigraphs with degree constraints

Speaker: Xu Baogang

Abstract: In 1996, Stiebitz confirmed a conjecture of Thomassen and proved that every graph of minimum degree at least s+t+1 has a partition (S,T) such that δ(G[S])≥ s and δ(G[T])≥ t. Then, some Stiebitz's type theorems appear on special families of graphs. Recently, Schweser and Stiebitz consider the analogous problem of multigraphs (multiedges are permitted), and generalize some conclusions from simple graphs to multigraphs. In this talk, we will present some recent progresses and still open problems on this topic.

Introduction of Speaker: Xu Baogang, graduated in 1997 from Shandong University with a degree of Doctor of Science, then went to the Institute of System Science of CAS for post-doctoral research; later, he became an associate research fellow in the Institute of System Science of CAS and now is a professor and doctoral supervisor in Nanjing Normal University. At present, he mainly focuses on the study of graph coloring and decomposition. He is the first one in China to carry out list coloring research, with main results published on JCTB. In the aspect of planar graph coloring, he solved an open problem put forward by Erdős in 1980s. The achievement he has made in Steinberg conjecture is the best until now. In terms of circular coloring, he has introduced the concept of minimally circular-imperfect graph and provided some structural properties of great significance.

Inviter: Wang Guanghui, Professor in the School of Mathematics

Time: 9:00 am April 15 (Monday)

Venue: 1032 Conference Hall, Block B of Zhixin Building, Central Campus

Organizer: Mathematics School of Shandong University