Positive mild solutions of periodic boundary value problems for fractional evolution equations

The periodic boundary value problem is discussed for a class of fractional evolution equations. the existence and uniqueness results of mild solutions for the associated linear fractional evolution equations are established,and the spectral radius of resolvent operator is accurately estimated. with the aid of the estimation,the existence and uniqueness results of positive mild solutions are obtained by using the monotone iterative technique. as an application that illustrates the abstract results,an example is given. copyright © 2012 jia mu and hongxia fan.