Improved random graph isomorphism. (English) Zbl 1157.05046

Summary: Canonical labeling of a graph consists of assigning a unique label to each vertex such that the labels are invariant under isomorphism. Such a labeling can be used to solve the graph isomorphism problem. We give a simple, linear time, high probability algorithm for the canonical labeling of a \(G(n,p)\) random graph for \[ p\in [\omega (\ln ^4n/n \ln\ln n), 1 - \omega (\ln^4n/n \ln\ln n)]. \] Our result covers a gap in the range of \(p\) in which no algorithm was known to work with high probability. Together with a previous result by Bollobás, the random graph isomorphism problem can be solved efficiently for \(p\in [\Theta (\ln n/n),1 - \Theta (\ln n/n)]\).


05C80 Random graphs (graph-theoretic aspects)
05C60 Isomorphism problems in graph theory (reconstruction conjecture, etc.) and homomorphisms (subgraph embedding, etc.)
05C85 Graph algorithms (graph-theoretic aspects)
05C78 Graph labelling (graceful graphs, bandwidth, etc.)
Full Text: DOI


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