Making Arbitrary Graphs Transitively Orientable: Minimal Comparability Completions
نویسندگان
چکیده
A transitive orientation of an undirected graph is an assignment of directions to itsedges so that these directed edges represent a transitive relation between the vertices ofthe graph. Not every graph has a transitive orientation, but every graph can be turnedinto a graph that has a transitive orientation, by adding edges. We study the problem ofadding an inclusion minimal set of edges to an arbitrary graph so that the resulting graphis transitively orientable. We show that this problem can be solved in polynomial time, andwe give a surprisingly simple algorithm for it.
منابع مشابه
Minimal comparability completions of arbitrary graphs
A transitive orientation of an undirected graph is an assignment of directions to its edges so that these directed edges represent a transitive relation between the vertices of the graph. Not every graph has a transitive orientation, but every graph can be turned into a graph that has a transitive orientation, by adding edges. We study the problem of adding an inclusion minimal set of edges to ...
متن کاملMinimal comparability completions
We study the problem of adding edges to a given arbitrary graph so that the resulting graph is a comparability graph, called a comparability completion of the input graph. Computing a comparability completion with the minimum possible number of added edges is an NP-hard problem. Our purpose here is to add an inclusion minimal set of edges to obtain a minimal comparability completion, which mean...
متن کاملMinimal Split Completions of Graphs
We study the problem of adding edges to a given arbitrary graph so that the resulting graph is a split graph, called a split completion of the input graph. Our purpose is to add an inclusion minimal set of edges to obtain a minimal split completion, which means that no proper subset of the added edges is sufficient to create a split completion. Minimal completions of arbitrary graphs into chord...
متن کاملSingle-Edge Monotonic Sequences of Graphs and Linear-Time Algorithms for Minimal Completions and Deletions
We study graph properties that admit an increasing, or equivalently decreasing, sequence of graphs on the same vertex set such that for any two consecutive graphs in the sequence their difference is a single edge. This is useful for characterizing and computing minimal completions and deletions of arbitrary graphs into having these properties. We prove that threshold graphs and chain graphs adm...
متن کاملMinimal split completions
We study the problem of adding an inclusion minimal set of edges to a given arbitrary graph so that the resulting graph is a split graph, called a minimal split completion of the input graph. Minimal completions of arbitrary graphs into chordal and interval graphs have been studied previously, and new results have been added recently. We extend these previous results to split graphs by giving a...
متن کامل