On a generalized fractional Du Bois-Reymond lemma and its applications

Abstract

In the paper, we derive a fractional version of the Du Bois-Reymond lemma for a generalized Riemann-Liouville derivative (derivative in the Hilfer sense). It is a generalization of well known results of such a type for the Riemann-Liouville and Caputo derivatives. Next, we use this lemma to investigate critical points of a some Lagrange functional (we derive the Euler-Lagrange equation for this functional).