Solving the Canonical Representation and Star System Problems for Proper Circular-Arc Graphs in Log-Space

Johannes Köbler; Sebastian Kuhnert; Oleg Verbitsky

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arXiv · 1202.4406

Solving the Canonical Representation and Star System Problems for Proper Circular-Arc Graphs in Log-Space

Johannes Köbler·Sebastian Kuhnert·Oleg Verbitsky

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Abstract

We present a logspace algorithm that constructs a canonical intersection model for a given proper circular-arc graph, where `canonical' means that models of isomorphic graphs are equal. This implies that the recognition and the isomorphism problems for this class of graphs are solvable in logspace. For a broader class of concave-round graphs, that still possess (not necessarily proper) circular-arc models, we show that those can also be constructed canonically in logspace. As a building block for these results, we show how to compute canonical models of circular-arc hypergraphs in logspace, which are also known as matrices with the circular-ones property. Finally, we consider the search version of the Star System Problem that consists in reconstructing a graph from its closed neighborhood hypergraph. We solve it in logspace for the classes of proper circular-arc, concave-round, and co-convex graphs.

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BibTeX RIS

Johannes Köbler, Sebastian Kuhnert, Oleg Verbitsky. 2013-12-05. Solving the Canonical Representation and Star System Problems for Proper Circular-Arc Graphs in Log-Space. https://arxiv.org/abs/1202.4406

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