Departamento de Matemáticas, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Spain ; Dipartimento di Matematica, Università di Pisa, Largo B. Pontecorvo 5, 56100 Pisa, Italy
Abstract:
We prove a family of identities that involve the solution to the following Cauchy problem:
and the -norm of the initial datum . As a consequence of these identities we shall deduce a lower bound for the local smoothing estimate proved by Constantin and Saut (1989), Sjölin (1987) and Vega (1988) and a uniqueness criterion for the solutions to the Schrödinger equation.