  We describe an effective algorithm for computing Seiberg-Witen invariants of
lens spaces. We apply it to two problems: (i) to compute the Froyshov
invariants of a large family of lens spaces; (ii) to show that the knowledge of
the Seiberg-Witten invariants of lens spaces is topologically equivalent to the
knowledge of its Casson-Walker invariant and of its Milnor-Turaev torsion. We
also use the results in problem (i) to derive several topological results
concerning the negative definite manifolds bounding a given lens space.
