ON SOLVABILITY OF LINEAR FRACTIONAL DIFFERENTIAL EQUATIONS IN BANACH SPACES∗

We describe a set of initial data in the abstract Cauchy problem for the linear equation with the Caputo fractional derivative and an unbounded linear closed operator A in a Banach space X Dα ∗ x(t) = Ax(t), m − 1 < α ≤ m ∈ N, dk dtk x(t)|t=0 = ξk, k = 0, . . . ,m − 1 for which the corresponding solutions can be represented by means of the MittagLeffler operator function. Some properties of the Mittag-Leffler operator function are given. Mathematics Subject Classification: primary 34G10, secondary 26A33, 45J05, 45K05