1 research outputs found
A characterization of Claw-free CIS graphs and new results on the order of CIS graphs
A graph is CIS if every maximal clique interesects every maximal stable set.
Currently, no good characterization or recognition algorithm for the CIS graphs
is known. We characterize graphs in which every maximal matching saturates all
vertices of degree at least two and use this result to give a structural,
efficiently testable characterization of claw-free CIS graphs. We answer in the
negative a question of Dobson, Hujdurovi\'c, Milani\v{c}, and Verret
[Vertex-transitive CIS graphs, European J. Combin. 44 (2015) 87-98] asking
whether the number of vertices of every CIS graph is bounded from above by the
product of its clique and stability numbers. On the positive side, we show that
the question of Dobson et al. has an affirmative answer in the case of
claw-free graphs