Escolano, Francisco, Hancock, Edwin R., Lozano, Miguel Angel Graph Similarity through Entropic Manifold Alignment SIAM Journal on Imaging Sciences. 2017, 10(2): 942-978. doi:10.1137/15M1032454 URI: http://hdl.handle.net/10045/68248 DOI: 10.1137/15M1032454 ISSN: 1936-4954 Abstract: In this paper we decouple the problem of measuring graph similarity into two sequential steps. The first step is the linearization of the quadratic assignment problem (QAP) in a low-dimensional space, given by the embedding trick. The second step is the evaluation of an information-theoretic distributional measure, which relies on deformable manifold alignment. The proposed measure is a normalized conditional entropy, which induces a positive definite kernel when symmetrized. We use bypass entropy estimation methods to compute an approximation of the normalized conditional entropy. Our approach, which is purely topological (i.e., it does not rely on node or edge attributes although it can potentially accommodate them as additional sources of information) is competitive with state-of-the-art graph matching algorithms as sources of correspondence-based graph similarity, but its complexity is linear instead of cubic (although the complexity of the similarity measure is quadratic). We also determine that the best embedding strategy for graph similarity is provided by commute time embedding, and we conjecture that this is related to its inversibility property, since the inverse of the embeddings obtained using our method can be used as a generative sampler of graph structure. Keywords:Graph similarity, Graph matching, Graph embedding, Graph kernels, Nonparametric entropy estimation Society for Industrial and Applied Mathematics info:eu-repo/semantics/article