Purpose To derive existence and comparison results for extremal solutions of nonlinear singular distributional initial value problems and boundary value problems. Main methods Fixed point results in ordered function spaces and recently introduced concepts of regulated and continuous primitive integrals of distributions. Maple programming is used to determine solutions of examples. Results New existence results are derived for the smallest and greatest solutions of considered problems. Novel results are derived for the dependence of solutions on the data. The obtained results are applied to impulsive differential equations. Concrete examples are presented and solved to illustrate the obtained results. MSC: 26A24, 26A39, 26A48, 34A12, 34A36, 37A37, 39B12, 39B22, 47B38, 47J25, 47H07, 47H10, 58D25
HeikkiläBoundary Value Problems2011,2011:24 http://www.boundaryvalueproblems.com/content/2011/1/24
R E S E A R C HOpen Access On singular nonlinear distributional and impulsive initial and boundary value problems
Seppo Heikkilä
Correspondence: sheikki@cc.oulu.fi Department of Mathematical Sciences, University of Oulu, BOX 3000, FIN90014, Oulu, Finland
Abstract Purpose:To derive existence and comparison results for extremal solutions of nonlinear singular distributional initial value problems and boundary value problems. Main methods:Fixed point results in ordered function spaces and recently introduced concepts of regulated and continuous primitive integrals of distributions. Maple programming is used to determine solutions of examples. Results:New existence results are derived for the smallest and greatest solutions of considered problems. Novel results are derived for the dependence of solutions on the data. The obtained results are applied to impulsive differential equations. Concrete examples are presented and solved to illustrate the obtained results. MSC:26A24, 26A39, 26A48, 34A12, 34A36, 37A37, 39B12, 39B22, 47B38, 47J25, 47H07, 47H10, 58D25 Keywords:distribution; primitive, integral; regulated, continuous; initial value problem, boundary value problem, singular, distributional
1 Introduction In this paper, existence and comparison results are derived for the smallest and great est solutions of first and second order singular nonlinear initial value problems as well as second order boundary value problems. Recently, similar problems are studied in ordered Banach spaces, e.g., in [14], by con verting problems into systems of integral equations, integrals in these systems being BochnerLebesgue or HenstockKurzweil integrals. A novel feature in the present study is that the righthand sides of the considered differential equations comprise distribu tions on a compact real interval [a,b]. Every distribution is assumed to have a primitive in the spaceRa,bof those functions from [a,b] toℝwhich are leftcontinuous on (a,b], rightcontinuous ata, and which have right limits at every point of (a,b). With this presupposition, the considered problems can be transformed into integral equations which include the regulated primitive integral of distributions introduced recently in [5]. The paper is organized as follows. Distributions on [a,b], their primitives, regulated primitive integrals and some of their properties, as well as a fixed point lemma are pre sented in Section 2. In Section 3, existence and comparison results are derived for the smallest and greatest solutions of first order initial value problems. A fact that makes the solution spaceRa,bimportant in applications is that it con tains primitives of Dirac delta distributionsδl,lÎ(a,b). This fact is exploited in