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

Prof. Emo Welzl and Prof. Bernd Gärtner

Mittagsseminar Talk Information |

**Date and Time**: Tuesday, May 16, 2023, 12:15 pm

**Duration**: 30 minutes

**Location**: OAT S15/S16/S17

**Speaker**: Michael Hoffmann

An obstacle representation of a graph G consists of a set of pairwise disjoint simply-connected closed regions in the plane and a one-to-one mapping of the vertices of G to points such that two vertices are adjacent in G if and only if the line segment that connects the two corresponding points does not intersect any obstacle. The obstacle number of a graph G is the smallest number of obstacles in an obstacle representation of G such that all obstacles are simple polygons; for the convex obstacle number, all obstacles must be convex polygons. In this talk, I will discuss lower bounds for obstacle numbers. Specifically, there is a constant c s.t. for every n there exists a graph on n vertices that has convex obstacle number at least cn. Joint work with Martin Balko, Steven Chaplick, Robert Ganian, Siddharth Gupta, Pavel Valtr, and Alexander Wolff.

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

Previous talks by year: 2023 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