Vertex Cover

In the mathematical discipline of graph theory, a vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. The problem of finding a minimum vertex cover is a classical optimization problem in computer science and is a typical example of an NP-hard optimization problem that has an approximation algorithm. Its decision version, the vertex cover problem, was one of Karp's 21 NP-complete problems and is therefore a classical NP-complete problem in computational complexity theory. Furthermore, the vertex cover problem is fixed-parameter tractable and a central problem in parameterized complexity theory.

The minimum vertex cover problem can be formulated as a half-integral linear program whose dual linear program is the maximum matching problem.

Covering-packing dualities
Covering problems Packing problems
Minimum set cover Maximum set packing
Minimum vertex cover Maximum matching
Minimum edge cover Maximum independent set

Read more about Vertex Cover:  Definition, Computational Problem, Vertex Cover in Hypergraphs

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