### Restricted Space Algorithms for Isomorphism on Bounded Treewidth Graphs

Bireswar Das, Jacobo TorÃ¡N & Fabian Wagner
The Graph Isomorphism problem restricted to graphs of bounded treewidth or bounded tree distance width are known to be solvable in polynomial time~\cite{Bo90},\cite{YBFT}.We give restricted space algorithms for these problems proving the following results: \begin{itemize} \item Isomorphism for bounded tree distance width graphs is in \Log\ and thus complete for the class. We also show that for this kind of graphs a canon can be computed within logspace. \item For bounded treewidth graphs, when both...