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113

answers:

2

A fast algorithm to find the size of the largest clique in a perfect graph(this one having odd cycles with at least 1 chord) with about 100 vertices ??

And is there any simpler method than brute force as this is a perfect graph and there should be a polynomial time solution to it. But I am not able to find the algorithm.

Does greedy coloring give optimal coloring in all perfect graphs??

+1  A: 

See page 296, with some work you should write the right linear programming constraint to solve this problem.

http://www.scribd.com/doc/5710463/Geometric-Algorithms-And-Combinatorial-Optimization

yogsototh
+1: Only answer which addresses perfect graphs, for which the clique problem is in P.
Moron
A: 

100 vertices? Pffft. Brute force it in a few seconds (perhaps fraction of a second) with Cliquer. http://users.tkk.fi/pat/cliquer.html

Chad Brewbaker
Can u explain the algorithm(I have seen the documentation) but in simpler terms
copperhead
Sure. First Cliquer defines a permutation of the vertices. I think by default it is in whatever order you used in the input. Secondly, cliquer iterates finding the largest clique in the set [i....n], from i = n-1 to i=1. Along the way it remembers the largest clique it has found so far and when testing for new cliques it prunes the search when it becomes apparent that from the previously calculated clique sizes it will be impossible for that path of the search to yield a larger clique.
Chad Brewbaker