Department of Computer Science | Institute of Theoretical Computer Science | CADMO

Theory of Combinatorial Algorithms

Prof. Emo Welzl and Prof. Bernd Gärtner

Mittagsseminar (in cooperation with M. Ghaffari, A. Steger, D. Steurer and B. Sudakov)

Mittagsseminar Talk Information

Date and Time: Tuesday, April 12, 2022, 12:15 pm

Duration: 30 minutes

Location: CAB G51

Speaker: Raphael Steiner

New bounds for relatives of Hadwiger's conjecture

In this talk, I will present some recent results on two variants of Hadwiger's conjecture. First, I will discuss the so-called Odd Hadwiger's conjecture, a strengthening of Hadwiger's conjecture proposed by Gerards and Seymour in 1995. First I will show a new upper bound for coloring graphs with no odd K_t-minor, thereby improving previous bounds for this problem, which comes along with a substantially simpler proof. Second, I will show a new bound of 2t-2 for clustered colorings of odd K_t-minor free graphs, in which we look for (possibly improper) colorings with monochromatic components of small size, this also significantly improves previous results. Third, I will discuss the so-called List Hadwiger's conjecture, which states that there exists a constant c such that every graph with no Kt-minor is ct-choosable (i.e., list colorable). I will present a new lower bound 2t-o(t) for list coloring K_t-minor free graphs which refutes a conjecture by Kawarabayashi and Mohar. Fourth, I will present a result saying that K_{s,t}-minor free graphs for large comparable s and t can have list chromatic number at least (1-o(1)(s+t+min(s,t)), this refutes a conjecture by Woodall.


Upcoming talks     |     All previous talks     |     Talks by speaker     |     Upcoming talks in iCal format (beta version!)

Previous talks by year:   2022  2021  2020  2019  2018  2017  2016  2015  2014  2013  2012  2011  2010  2009  2008  2007  2006  2005  2004  2003  2002  2001  2000  1999  1998  1997  1996  

Information for students and suggested topics for student talks


Automatic MiSe System Software Version 1.4803M   |   admin login