EXISTENCE OF POSITIVE SOLUTIONS FORSINGULAR BOUNDARY VALUE PROBLEMS FOR4TH-ORDER IMPULSIVE DIFFERENTIALEQUATIONS

摘要

Using the lower and upper solution technique, we present some necessary andsufficient conditions for the existence of PC~2([0, 1],R+)as well asPC~3([0, 1],R+) posi-tive solutions of singular boundary value problems for fourth-order impulsive differentialequations.