%0 Journal Article %T Dirichlet forms and stochastic completeness of graphs and subgraphs %A Matthias Keller %A Daniel Lenz %J Mathematics %D 2009 %I arXiv %X We study Laplacians on graphs and networks via regular Dirichlet forms. We give a sufficient geometric condition for essential selfadjointness and explicitly determine the generators of the associated semigroups on all $\ell^p$, $1\leq p < \infty$, in this case. We characterize stochastic completeness thereby generalizing all earlier corresponding results for graph Laplacians. Finally, we study how stochastic completeness of a subgraph is related to stochastic completeness of the whole graph. %U http://arxiv.org/abs/0904.2985v2