Discrete Mathematics
Information Processing Letters
Triangle-free four-chromatic graphs
Discrete Mathematics
On the NP-completeness of the k-colorability problem for triangle-free graphs
Discrete Mathematics
Triangle-free graphs with large chromatic numbers
Discrete Mathematics
Combinatorica
Distance-hereditary graphs are clique-perfect
Discrete Applied Mathematics
Partial characterizations of clique-perfect graphs I: Subclasses of claw-free graphs
Discrete Applied Mathematics
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A graph G is clique-perfect if the cardinality of a maximum clique-independent set of H equals the cardinality of a minimum clique-transversal of H, for every induced subgraph H of G. A graph G is coordinated if the minimum number of colors that can be assigned to the cliques of H in such a way that no two cliques with non-empty intersection receive the same color equals the maximum number of cliques of H with a common vertex, for every induced subgraph H of G. Coordinated graphs are a subclass of perfect graphs. The complete lists of minimal forbidden induced subgraphs for the classes of clique-perfect and coordinated graphs are not known, but some partial characterizations have been obtained. In this paper, we characterize clique-perfect and coordinated graphs by minimal forbidden induced subgraphs when the graph is either paw-free or {gem, W"4, bull}-free, both superclasses of triangle-free graphs.