Magnetic virial identities, weak dispersion and Strichartz inequalities

We show a family of virial-type identities for the Schr\"odinger and wave equations with electromagnetic potentials. As a consequence, some weak dispersive inequalities in space dimension $n\geq3$, involving Morawetz and smoothing estimates, are proved; finally, we apply them to prove Strichartz inequalities for the wave equation with a non-trapping electromagnetic potential with almost Coulomb decay.