Closed-form representation of the iterated L-fractional integral operator LJ^m_α and convolution structure
Determine whether the iterated L-fractional integral operator LJ^m_α admits closed-form expressions, in particular whether LJ^m_α can be represented as a convolution operator analogous to the Caputo case, and consequently whether solutions depend on a new two-parameter Mittag-Leffler-type function.
References
Is it possible to find closed-form expressions for the composed integral operator LJmα? ... We wonder whether LJmα could be given as a convolution, like in the Caputo case, and whether the solution x(t) would depend on some new two-parameter Mittag-Leffler-type function.
                — Theory on linear L-fractional differential equations and a new Mittag-Leffler-type function
                
                (2403.00341 - Jornet, 1 Mar 2024) in Section 8, Open Problems