Non-linear operations in the Sobolev spaces Hps and the Besov spaces Bps,q and regularity for the semi-linear equations

The properties of certain non-linear operations in the Sobolev spaces Hps, 1 < p < infinity, s is an element of R and the Besov spaces Bps,q 1 ≤ p,q ≤ infinity s is an element of R are studied. The first and the second wave front sets of the solutions of semi-linear equations are estimated. (author). 12 refs