Matroid Reinforcement

For a matroid M, Edmonds proved that its ground set contains k disjoint bases if and only if |A| >= k(r(E) -- r( ¯A)) for every subset A of the ground set E. Here r is the rank function of M. We study the system of inequalities x(A) >= k(r(E) -- r( ¯A)), 0 <= x <= u. We show that if u is integer valued then this defines a polyhedron with integer extreme points. We also show that this is a TDI system. We give a simple combinatorial algorithm for solving the associated optimization problem. Related results have been obtained by Frank & Tardos with the use of generalized polymatroids.

By: Francisco Barahona, Herve Kerivin

Published in: RC22634 in 2002

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