Characterizations, probe and sandwich problems on (k, ℓ)-cographs.

Faria Luerbio , Vinicius Fernandes dos Santos , Fernanda Couto , Luerbio Faria , Sylvain Gravier (1, 2) , Sulamita Klein , Vinicius F dos Santos

1 IF - Institut Fourier
2 SFR MAM - Maths à Modeler

A cograph is a graph without induced P4. A graph G is (k,) if its vertex set can be partitioned into at most k independent sets and cliques. Threshold graphs are cographs-(1, 1). We proved recently that cographs-(2, 1) are their generalization and, as threshold graphs, they can be recognized in linear time. graph sandwich problems for property Π (Π-sp) were defined by Golumbic et al. as a natural generalization of recognition problems. probe partitioned problems are particular cases of graph sandwich problems. In this paper we show that, similarly to probe threshold graphs and probe cographs, probe cographs-(2, 1) and probe join of two thresholds are recognizable in polynomial time. In contrast, although cograph-sp and thresholdsp are polynomially solvable problems, we prove that cograph-(2, 1)-sp and join of two thresholds-sp are NP-complete problems.

Mots clés: Graph Sandwich Problems; Cograph-; (2; 1)-Join of Two Threshold Graphs

Domaines: Mathématique discrète [cs.DM]

Faria Luerbio, Vinicius Fernandes dos Santos, Fernanda Couto, Luerbio Faria, Sylvain Gravier, et al.. Characterizations, probe and sandwich problems on (k, ℓ)-cographs.. Discrete Applied Mathematics, 2020. ⟨hal-03015850⟩