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Paper:

TR07-068 | 24th July 2007 00:00

The Isomorphism Problem for Planar 3-Connected Graphs is in Unambiguous Logspace

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TR07-068
Authors: Thomas Thierauf, Fabian Wagner
Publication: 24th July 2007 22:28
Downloads: 1121
Keywords: 


Abstract:

The isomorphism problem for planar graphs is known to be efficiently solvable. For planar 3-connected graphs, the isomorphism problem can be solved by efficient parallel algorithms, it is in the class AC^1.

In this paper we improve the upper bound for planar 3-connected graphs to unambiguous logspace, in fact to the intersection of UL and co-UL. As a consequence of our method we get that the isomorphism problem for oriented graphs is in NL. We also show that these problems are hard for logspace.



ISSN 1433-8092 | Imprint