Teoria degli operatori intermedi e applicazioni: risultati generali

Lanzara, Flavia

Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Matematica e applicazioni, Série 9, Tome 3 (1992) no. 2, pp. 79-101

Résumé

Problems of the following kind are considered: \( (T u,v)_{H} = (f,v)_{S}\), \(f \in S \), \( u \in H \), \( \forall v \in H \), vector \( f \) is given, vector \( u \) is the «unknown». \( H \) is a subspace of the Hilbert space \( S \). \( T \) is a linear operator from \( H \) to \( H \) which satisfies suitable hypotheses. By using the theory of intermediate operators methods for the calculus of the «Green operators» and of the relevant «Green functions» are given. Explicit «a priori» estimates are obtained which are as close as we wish to the optimal ones.