EXISTENCE OF EXTREMAL SOLUTIONS OF PBVP FOR FIRST ORDER DIFFERENTIAL EQUATIONS
In this paper, we consider the existence of solutions of periodic boundary value problems (PBVP) for first order differential equations. By using Mönch and Von Harten inequality, we prove the existence of extremal solutions of (PBVP) in any of four groups different conditions in Banach spaces.
Banach space, dual space, periodic boundary value problems, minimal solutions, maximal solutions.