The article [2] is devoted to the study of the local fractional derivative introduced by Kolvankar and Gangal [6] which
is based on a localization of the classical Riemann–Liouville fractional (RL) derivative and some of its consequences on the
local regularity of functions. The RL derivative is in general very complicated to compute. In [2] we have announced that the
Kolvankar–Gangal derivative is equal to a simple difference quotient called the α-derivative (see [2], Definition 1.3, p. 725).
The proof of this theorem in [2] is incorrect. The aim of this note is first to give a proof of this result and also to precise and
correct some of our results and notations in order to avoid confusions in particular concerning functional spaces.