RT Journal Article T1 Fractional Langevin Equation Involving Two Fractional Orders: Existence and Uniqueness Revisited A1 Fazli, Hossein A1 Sun, HongGuang A1 Nieto Roig, Juan José K1 Fractional Langevin equation K1 Mittag–Leffler function K1 Prabhakar integral operator K1 Existence K1 Uniqueness AB We consider the nonlinear fractional Langevin equation involving two fractional orders with initial conditions. Using some basic properties of Prabhakar integral operator, we find an equivalent Volterra integral equation with two parameter Mittag–Leffler function in the kernel to the mentioned equation. We used the contraction mapping theorem and Weissinger’s fixed point theorem to obtain existence and uniqueness of global solution in the spaces of Lebesgue integrable functions. The new representation formula of the general solution helps us to find the fixed point problem associated with the fractional Langevin equation which its contractivity constant is independent of the friction coefficient. Two examples are discussed to illustrate the feasibility of the main theorems PB MDPI YR 2020 FD 2020 LK http://hdl.handle.net/10347/23641 UL http://hdl.handle.net/10347/23641 LA eng NO Fazli, H.; Sun, H.; Nieto, J.J. Fractional Langevin Equation Involving Two Fractional Orders: Existence and Uniqueness Revisited. Mathematics 2020, 8, 743 NO The authors are thankful to the Editor(s) and reviewers of the manuscript for their helpful comments. The work of H. Fazli and H. Sun was supported by the National Key R&D Program of China (2017YFC0405203), the National Natural Science Foundation of China under Grant No. 11972148. The reserach of J. J. Nieto was partially supported by Xunta de Galicia, ED431C 2019/02, and by project MTM2016-75140-P of AEI/FEDER (Spain) DS Minerva RD 24 abr 2026