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

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 AC1 . In this paper we improve the upper bound for planar 3-connected graphs to unambiguous logspace, in fact to UL coUL. As a consequence of our method we get that the isomorphism problem for oriented graphs is in NL. We also show that the problems are hard for logspace.

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Thomas Thierauf, Fabian Wagner
• Keywords: CORR 2008, Education, Isomorphism Problem, Planar 3-connected Graphs, Planar Graphs