Preliminaries
The operator, denoted by q
a t D is fractional differential operator, which is a
combined differentiation and integration operator commonly used in fractional calculus.
There are different definitions for fractional derivatives. The most commonly used
definitions are the Riemann-Liouville, Caputo, and Grunwald-Letkinov definitions. These
definitions are the following.
Riemann-Liouville definition: