“…are closely related to existence and uniqueness results for solutions of operator equations involving C f and S h . Also, for example, in [29], it is proved, for the integral equation of Volterra type in the Henstock setting, that the existence of a continuous solution depends, among other conditions, on the property of mapping continuous functions into Henstock-integrable functions, satisfied by the involved non-autonomous superposition operator; in [15], the authors provide, in the Henstock-Kurzweil-Pettis setting, existence and closure results for integral problems driven by regulated functions, both in single-and set-valued cases ( [14]). Hence, in many fields of non-linear analysis and its applications (in particular to integral equations), the following problem becomes of interest:…”