This paper studies the existence of symmetric positive solutions for a second order nonlinear semipositone boundary value problem with integral boundary conditions by applying the Krasnoselskii fixed point theorem. Emphasis is put on the fact that the nonlinear term f may take negative value. An example is presented to demonstrate the application of our main result.

In this paper, we establish two fixed point theorems of Krasnoselskii type for the sum of A + B, where A is a compact operator and I − B may not be injective. Our results extend previous ones. As an application, we apply such results to obtain some existence results of periodic solutions for delay integral equations and then give three instructive examples.

Let [Formula: see text], [Formula: see text], and [Formula: see text] be a strongly monotone and Lipschitz mapping. A Krasnoselskii-type sequence is constructed and proved to converge strongly to the unique solution of [Formula: see text]. Furthermore, our technique of proo f is of independent interest.

In this paper we investigate the existence of positive solutions of the q-difference equation −D2 qu(t) = a(t) f(u(t)) with some boundary conditions by applying a fixed point theorem in cones. 1. Preliminaries In many of the mathematical models in science such as models of chemical problems, population or concentration in biology, and many problems in physics and economics, we need to investiga...

In this paper, we consider two new uniqueness results for fuzzy fractional differential equations (FFDEs) involving Riemann-Liouville generalized H-differentiability with the Nagumo-type condition and the Krasnoselskii-Krein-type condition. To this purpose, the equivalent integral forms of FFDEs are determined and then these are used to study the convergence of the Picard successive approximati...

where 2 < α ≤ 3, D denotes the Riemann-Liouville fractional derivative, λ is a positive constant, f (t, x) may change sign and be singular at t = 0, t = 1, and x = 0. By means of the Guo-Krasnoselskii fixed point theorem, the eigenvalue intervals of the nonlinear fractional functional differential equation boundary value problem are considered, and some positive solutions are obtained, respecti...

We establish the existence of one or more than one positive periodic solutions of singular systems of first order difference equations ∆x(k) =−a(k)x(k)+λb(k)f(x(k)). The proof of our results is based on the Krasnoselskii fixed point theorem in a cone.

Sufficient conditions are given for the existence of positive solutions of a boundary-value problem concerning a second-order delay differential equation with damping and forcing term whose the delayed part is an actively bounded function, a meaning which is introduced in this paper. The Krasnoselskii fixed point theorem on cones in Banach spaces is used.

The existence and multiplicity of positive periodic solutions for first non-autonomous singular systems are established with superlinearity or sublinearity assumptions at infinity for an appropriately chosen parameter. The proof of our results is based on the Krasnoselskii fixed point theorem in a cone. 2011 Elsevier Inc. All rights reserved.