Sciweavers

127 search results - page 1 / 26
» The Directed Planar Reachability Problem
Sort
View
FSTTCS
2005
Springer
14 years 4 months ago
The Directed Planar Reachability Problem
We investigate the s-t-connectivity problem for directed planar graphs, which is hard for L and is contained in NL but is not known to be complete. We show that this problem is log...
Eric Allender, Samir Datta, Sambuddha Roy
COCO
2007
Springer
114views Algorithms» more  COCO 2007»
14 years 5 months ago
Directed Planar Reachability is in Unambiguous Log-Space
We make progress in understanding the complexity of the graph reachability problem in the context of unambiguous logarithmic space computation; a restricted form of nondeterminism....
Chris Bourke, Raghunath Tewari, N. V. Vinodchandra...
COCO
2010
Springer
152views Algorithms» more  COCO 2010»
14 years 2 months ago
A Log-Space Algorithm for Reachability in Planar Acyclic Digraphs with Few Sources
Designing algorithms that use logarithmic space for graph reachability problems is fundamental to complexity theory. It is well known that for general directed graphs this problem...
Derrick Stolee, Chris Bourke, N. V. Vinodchandran
FCT
2009
Springer
14 years 2 months ago
Reachability in K3, 3-Free Graphs and K5-Free Graphs Is in Unambiguous Log-Space
We show that the reachability problem for directed graphs that are either K3,3-free or K5-free is in unambiguous log-space, UL coUL. This significantly extends the result of Bour...
Thomas Thierauf, Fabian Wagner
ECCC
2010
143views more  ECCC 2010»
13 years 8 months ago
Space-Efficient Algorithms for Reachability in Surface-Embedded Graphs
We consider the reachability problem for a certain class of directed acyclic graphs embedded on surfaces. Let G(m, g) be the class of directed acyclic graphs with m = m(n) source ...
Derrick Stolee, N. V. Vinodchandran