“…Second, we adapt a result of Burq [2002], which provides Strichartz estimates without loss for a nontrapping problem, with a metric that equals the identity outside a compact set. The proof relies on a local smoothing effect for the free evolution exp (it D ), first observed independently by Constantin and Saut [1989], Sjölin [1987], and Vega [1988] in the flat case, and then by Doi [1996] on nontrapping manifolds and by Burq et al [2004a] on exterior domains. Following a strategy suggested by Staffilani and Tataru [2002], we prove that away from the obstacle the free evolution enjoys the Strichartz estimates exactly as for the free space.…”