Some generalizations of comparison results for fractional differential equations

In this paper, by using the technique of upper and lower solutions together with the theory of strict and nonstrict fractional differential inequalities involving Riemann-Liouville differential operator of order q, 0 < q < 1, some necessary comparison results for further generalizations of several dynamical concepts are obtained. Furthermore, these results are extended to the finite systems of fractional differential equations. (C) 2011 Elsevier Ltd. All rights reserved.