© 1997 by London Mathematical Society
© The London Mathematical Society
Unbounded Translation Invariant Operators and the Derivation Property
Fachbereich 17Mathematik, University-GH Paderborn 33095 Paderborn, Germany. E-mail: dirka{at}uni-paderborn.de
Received 20 February 1995. Revision received 22 June 1995.
We are going to investigate translation invariant derivations on Lp spaces of locally compact abelian groups, 1
p<
. By these we mean densely defined closed linear operators which commute with translations and obey a Leibniz rule, that is, T(fg)=(Tf)·g+f·(Tg); see Definition 1 for details.
The original motivation for studying these operators was to find an abstract description of constant coefficient partial differential operators as a link to perturbation theory which is usually formulated in terms of abstract operator theoretic notions. This fits, for example, Schrödinger operator theory (as in [1]). Here, in view of the applications to perturbation theory, the point is that this identification is not just a formal one but includes assertions about domains (Theorem 1).
In this paper, however, we shall concentrate on groups other than Rn.