On evolutionary equations with material laws containing fractional integrals

摘要

A well-posedness result for a time-shift invariant class of evolutionary operator equations involving material laws with fractional time-integrals of order alpha is an element of]0, 1[ is considered. The fractional derivatives are defined via a function calculus for the (time-) derivative established as a normal operator in a suitable L-2-type space. Employing causality, we show that the fractional derivatives thus obtained coincide with the Riemann-Liouville fractional derivative. We exemplify our results by applications to a fractional Fokker-Planck equation, equations describing super-diffusion and sub-diffusion processes, and a Kelvin-Voigt type model in fractional visco-elasticity. Moreover, we elaborate a suitable perspective to deal with initial boundary value problems. Copyright (C) 2014 JohnWiley & Sons, Ltd.