a IMECC-UNICAMP, 13081-970 Campinas, São Paulo, SP, Brazil b Instituto de Matemática Pura e Aplicada, Estrada Dona Castorina, 110 Jardim Botânico, 22460-320 Rio de Janeiro, RJ, Brazil
Abstract:
We prove that, if a sufficiently smooth solution u to the initial value problem associated with the equation