Characterising circular-arc contact B0B_0-VPG graphs

A contact $B_0$-VPG graph is a graph for which there exists a collection of nontrivial pairwise interiorly disjoint horizontal and vertical segments in one-to-one correspondence with its vertex set such that two vertices are adjacent if and only if the corresponding segments touch. It was shown by Deniz et al. that Recognition is $\mathsf{NP}$-complete for contact $B_0$-VPG graphs. In this paper we present a minimal forbidden induced subgraph characterisation of contact $B_0$-VPG graphs within the class of circular-arc graphs and provide a polynomial-time algorithm for recognising these graphs

Characterising Chordal Contact: Bo-VPG Graphs

A graph G is a Bo- VPG graph if it is the vertex intersection graph of horizontal and vertical paths on a grid. A graph G is a contact Bo- VPG graph if the vertices can be represented by interiorly disjoint horizontal or vertical paths on a grid and two vertices are adjacent if and only if the corresponding paths touch. In this paper, we present a minimal forbidden induced subgraph characterisation of contact Bo-VPG graphs within the class of chordal graphs and provide a polynomial-time algorithm for recognising these graphs