Title：Fractional coloring of planar graphs

Abstract：Let $a,b$ be two integers with $a\geq 2b$. A graph $G$ is $(a:b)$-colorable if there exists an assignment of $b$-element subsets of $\{1,\ldots,a\}$ to vertices of $G$ such that sets assigned to adjacent vertices are disjoint. The fractional chromatic number of G, denoted by $\chi_f(G)$, is the infimum of the fractions $a/b$ such that G admits an $(a:b)$-coloring. The fractional coloring was first introduced in 1973 to seek for a proof of the Four Color Problem. In this talk, we will talk about some results on fractional coloring of planar graphs.

Speaker：Xiaohulan Hu, Ph.D., Central China Normal University. Her research interests include graph theory, especially on graph colorings.

Date：2:00pm-3:00pm 2022-11-10 (Thursday).

Tencent Meeting ID：227-556-401

Organizer：School of Mathematical Science

Students and teachers who are interested in graph theory are welcome.