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arXiv · 2006.16991

Precedence thinness in graphs

Flavia Bonomo-Braberman·Fabiano S. Oliveira·Moysés S. Sampaio Jr.·Jayme L. Szwarcfiter
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Abstract

Interval and proper interval graphs are very well-known graph classes, for which there is a wide literature. As a consequence, some generalizations of interval graphs have been proposed, in which graphs in general are expressed in terms of $k$ interval graphs, by splitting the graph in some special way. As a recent example of such an approach, the classes of $k$-thin and proper $k$-thin graphs have been introduced generalizing interval and proper interval graphs, respectively. The complexity of the recognition of each of these classes is still open, even for fixed $k \geq 2$. In this work, we introduce a subclass of $k$-thin graphs (resp. proper $k$-thin graphs), called precedence $k$-thin graphs (resp. precedence proper $k$-thin graphs). Concerning partitioned precedence $k$-thin graphs, we present a polynomial time recognition algorithm based on $PQ$-trees. With respect to partitioned precedence proper $k$-thin graphs, we prove that the related recognition problem is \NP-complete for an arbitrary $k$ and polynomial-time solvable when $k$ is fixed. Moreover, we present a characterization for these classes based on threshold graphs.

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Flavia Bonomo-Braberman, Fabiano S. Oliveira, Moysés S. Sampaio Jr., Jayme L. Szwarcfiter. 2020-06-30. Precedence thinness in graphs. https://doi.org/10.1016/j.dam.2021.05.020

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