연 사 : Prof. Thomas Mattman (California State University, Chico)

제 목 : There are too many knotted graphs!

일 시 :  2019년 7월 11일 목요일 오전 11시 30분

장 소 : 이화여자대학교 종합과학관 A동 317호

초 록 : The powerful Graph Minor Theorem of Robertson and Seymour ensures that, for any graph property, whatsoever, there is an associated finite list of graphs that are minor minimal with respect to that property. For example, with Thomas, they show that the seven graphs in the Petersen family are exactly the minor minimal intrinsic linked (MMIL) graphs.

  A graph is intrinsically linked (knotted) if every embedding in $\R^3$ has a pair of non-trivially linked cycles (a non-trivially knotted cycle).Through 2003, 41 MMIK (minor minimal intrinsically knotted) graphs were known. We have 220 new examples and our methods suggest there are likely many, many more.''