We know of the minimum weight perfect matching problem in general graphs which can be solved using a primal-dual algorithm. Assume, we have an additional constraint specifying the exact number of edges that the matching can use. In other words, given a graph G=(V,E) with m=|E| and an integer k, where m and k are different in general, we need to find a matching of minimum weight that uses exactly k edges.
What is known about the problem? Do we have a polynomial time algorithm for the problem?