Demonstratio Mathematica (Aug 2025)
Solution of nonlinear Langevin equations involving Hilfer-Hadamard fractional order derivatives and variable coefficients
Abstract
This study innovates a novel technique of the nonlinear fractional Langevin equation of Hilfer-Hadamard type, incorporating an initial condition. The research demonstrates that this problem can be reformulated as an integral equation featuring a Mittag-Leffler function within the kernel. Through rigorous analysis, we establish the existence and uniqueness of solutions for this problem without imposing a contractive assumption. Furthermore, the study extends these findings to encompass two specific types of fractional differential equations characterized by two fractional derivatives and a variable coefficient. Theoretical conclusions are supported by the provision of two illustrative examples.
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