New Grüss’s inequalities estimates considering the φ-fractional integrals

Careful study of applied sciences and their development requires us to expand the scope of analytical studies. We aim during introducing the current manuscript to rediscover and present Grüss inequality in a new framework. In order to do that, we use the recently generalized proportional fractional integral operator for a certain function with respect to another continuous and strictly increasing function. Furthermore, we prove some new related inequalities using the current fractional integral operator. Some special cases of the presented results will be discussed.