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In this paper, using fixed point index and the mixed monotone technique, we present some multiplicity and uniqueness results for the singular nonlocal boundary value problems involving nonlinear integral conditions. Our nonlinearity may be singular in its dependent variable and it is allowed to change sign. [ABSTRACT FROM AUTHOR]

In this paper, using the theory of fixed point index on a cone and the Leray-Schauder fixed point theorem, we present the multiplicity of positive solutions for the singular nonlocal boundary-value problems involving nonlinear integral conditions and the existence of at least one positive solution for the singular nonlocal boundary-value problems with sign-changed nonlinearities. [ABSTRACT FROM AUTHOR]

In this paper, using fixed-point index theory and approximation techniques, we consider the existence and multiplicity of fixed points of some nonlinear operators with singular perturbation. As an application we consider the existence and multiplicity of positive solutions of singular systems of multi-point boundary value problems, which improve the results in the literature. [ABSTRACT FROM AUTHOR]

Abstract  The existence of at least one positive solution and the existence of multiple positive solutions are established for the singular second-order boundary value problem $$\left\{\begin{array}{l}{\frac{1}{p(t)}(p(t)x'(t))'}+\Phi(t)f(t,x,px')=0,\quad 0 using the fixed point index, where f may be singular at x=0 and px′=0. [ABSTRACT FROM AUTHOR]

Positive solutions to the singular initial-boundary value problems x″ = - f(t, xt), 0 < t < 1, x0 = 0, x(1) = 0, are obtained by applying the Schauder fixed-point theorem, where xt(u) = x(t+u) (0 ≤ t ≤ 1) on [-r, 0] and f(.,.) : (0, 1) × (C+\{0})→R+(C+ = {x ϵ C([-r, 0], R), x(t) ≥ 0, ∀t ϵ [-r, 0]}) may be singular at φ(u) = 0 (-r ≤ u ≤ 0) and t = 0. As an application, an example is given to demonstrate our result. [ABSTRACT FROM AUTHOR]

Abstract  The existence of multiple positive solutions for the singular Dirichlet boundary-value problem $$\begin{array}{*{20}c} {{x^{{\prime \prime }} + \Phi {\left( t \right)}f{\left( {t,x{\left( t \right)},x^{\prime } {\left( t \right)}} \right)} = 0,\,\,\,\,0 is presented by using the fixed point index; here f may be singular at x = 0. [ABSTRACT FROM AUTHOR]