Consider the Lp-realization Opp(a) of a pseudodifferential operator with symbol a ϵsm p, 0having constant coefficients. We show that for a certain class of symbols the spectrum of Opp(a) is independent of p. This implies that Opp(a) generates an TV-times integrated semigroup on W(W) for a certain N if and only if pOpp(a)≠ ∅ and the numerical range of a is contained in a left half-plane. Our method allows us also to construct examples of operators generating integrated semigroups on Lp(Rn) if and only if p is sufficiently close to 2.
ASJC Scopus subject areas
- 数学 (全般)