Title    name
2017 Discrete Math 세미나
 
  Title
  Speaker Bernard Lidicky
  Date 2017-03-07
  Host
  Place KAIST
  File  의 1 번째 Real Media 동영상입니다.   
 
Abstract : A well known theorem of Grötzsch states that every planar graph is 3-colorable. We will show a simple proof based on a recent result of Kostochka and Yancey on the number of edges in 4-critical graphs. Then we show a strengthening of the Grötzsch’s theorem in several different directions. Based on joint works with Ilkyoo Choi, Jan Ekstein, Zdeněk Dvořák, Přemek Holub, Alexandr Kostochka, and Matthew Yancey.