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 and B. Sudakov)

Mittagsseminar Talk Information

Date and Time: Thursday, January 12, 2006, 12:15 pm

Duration: This information is not available in the database

Location: This information is not available in the database

Speaker: Samuel Zürcher

On 0-1-matrices and small excluded submatrices

We consider 0/1 matrices and say that an n*n matrix A contains a k*l matrix P (the pattern) if and only if we can find a submatrix B of A (that is obtained by deleting rows and columns of A) so that (P)i,j = 1 implies (B)i,j = 1. Otherwise, we say that A avoids P. For a given pattern P, we are interested in the maximum number of 1 entries that an n*n matrix can have avoiding the pattern P; written as ex(n, P). This extremal function is known for all patterns with at most four 1 entries and each one of those patterns is member in one of five classes; we'll show examples for each of those classes and sketch some of the proofs for the bounds on ex(n, P). In a second part of the talk, we'll show reductions that can be used to determine ex(n, P') for a pattern P' with previously unknown complexity, based on the knowledge of the complexity of a somehow related pattern P.

This talk is mainly based on work by Tardos, Marcus, Füredi, Hajnal, and Keszegh.


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

Previous talks by year:   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