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Explore Vertex Cover NP-completeness proof, 3DM example, and yacht owner puzzle. Understand Planar 3SAT, Strongly Planar CNF, 2-3SAT.
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Integer Programming TSP Knapsack VC HC 3DM Partition Planar 3SAT 3SAT SAT
Vertex Cover • Given a graph G=(V,E), find a minimum subset C of vertices such that every edge is incident to a vertex in C.
Decision Version • Given a graph G=(V,E) and positive integer k < |V|, is there a vertex cover C of size at most k?.
Vertex-Cover is NP-complete Proof.
Example of 3DM • Messrs. Spinnaker, Buoy, Luff, Gybe, and Windward are yacht owners. Each has a daughter, and each has named his yacht after the daughter of one of the others. • Mr. Spinnaker’s yacht, the Iris, is named after Mr. Buoy’s daughter. Mr. Buoy’s own yacht is the Daffodil; Mr. Windward’s yacht is the Jonquil; Mr. Gybe’s, the Anthea. • Daffodil is the daughter of the owner of the yacht which is named after Mr. Luff’s daughter. Mr. Windward’s daughter is named Lalage. • Who is Jonquil’s father?
Puzzle Answer