  Finding a stable matching is one of the central problems in algorithmic game
theory. If participants are allowed to have ties and incomplete preferences,
computing a stable matching of maximum cardinality is known to be NP-hard. In
this paper we present a $(3L-2)/(2L-1)$-approximation algorithm for the stable
matching problem with ties of size at most $L$ and incomplete lists. Our result
matches the known lower bound on the integrality gap for the associated LP
formulation.
