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Cover-incomparability graphs of posets. (English) Zbl 1219.06004
Summary: Cover-incomparability graphs (C-I graphs, for short) are introduced, whose edge-set is the union of edge-sets of the incomparability and the cover graph of a poset. Posets whose C-I graphs are chordal (resp. distance-hereditary, Ptolemaic) are characterized in terms of forbidden isometric subposets, and a general approach for studying C-I graphs is proposed. Several open problems are also stated.

##### MSC:
 06A07 Combinatorics of partially ordered sets 05C70 Edge subsets with special properties (factorization, matching, partitioning, covering and packing, etc.) 05C75 Structural characterization of families of graphs
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