Integral Operators in b-Metric and Generalized b-Metric Spaces and Boundary Value Problems

We study fixed-point theorems of contractive mappings in b-metric space, cone b-metric space, and the newly introduced extended b-metric space. To generalize an existence and uniqueness result for the so-called Phi s functions in the b-metric space to the extended b-metric space and the cone b-metric space, we introduce the class of Phi M functions and apply the H & ouml;lder continuous condition in the extended b-metric space. The obtained results are applied to prove the existence and uniqueness of solutions and positive solutions for nonlinear integral equations and fractional boundary value problems. Examples and numerical simulation are given to illustrate the applications.