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

Prof. Emo Welzl and Prof. Bernd Gärtner

Mittagsseminar Talk Information |

**Date and Time**: Thursday, April 22, 2021, 12:15 pm

**Duration**: 30 minutes

**Location**: Zoom: conference room

**Speaker**: Hung Hoang

Suppose we run a train on a directed (multi-)graph, where every vertex has out-degree 2 and is equipped with a switch. At the beginning, the switch at each vertex points to one of the two outgoing edges. When the train reaches a vertex, it will traverse along the edge pointed by the switch, and then the switch at that vertex shifts to the other outgoing edge. Given such a graph with an origin vertex o and a destination vertex d, the problem is to decide if the train starting from o can reach d.

The problem above is called ARRIVAL. It is in NP and co-NP, but not known to be in P. The currently best algorithms have runtime 2^ϴ(n) where n is the number of vertices. This is not much better than just performing the pseudorandom walk. In this talk, I will present a subexponential algorithm with runtime 2^O(√n log n).

Joint work with Bernd Gärtner and Sebastian Haslebacher

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

Previous talks by year: 2024 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