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

Prof. Emo Welzl and Prof. Bernd GÃ¤rtner

Mittagsseminar Talk Information |

**Date and Time**: Tuesday, October 20, 2009, 12:15 pm

**Duration**: This information is not available in the database

**Location**: CAB G51

**Speaker**: Jan Foniok

A Z-matrix is a square matrix whose off-diagonal elements are non-positive. A P-matrix is a square matrix whose principal minors are positive. A K-matrix is a matrix that is both a Z-matrix and a P-matrix.

In 1962, Fiedler and Pták listed thirteen equivalent conditions for a Z-matrix to be a K-matrix. Some of them concern the sign structure of some vectros; we generalize these conditions in the context of oriented matroids and prove their equivalence in this purely combinatorial context, using no wild linear algebra.

Our motivation to do this stems from the linear complementarity problem. A by-product of our theorem is another proof that LCP for K-matrices can be solved in linear time even by the drunken pivotter.

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