Construction of upper and lower solutions for singular discrete initial and boundary value problems via inequality theory.
Using Fan’s Min-Max Theorem we investigate existence of solutions and their dependence on parameters for some second order discrete boundary value problem. The approach is based on variational methods and solutions are obtained as saddle points to the relevant Euler action functional.
Using the fixed point theorems of Banach and Schauder we discuss the existence, uniqueness and stability of continuous solutions of a polynomial-like iterative equation with variable coefficients.
Given a probability space (Ω,, P) and a closed subset X of a Banach lattice, we consider functions f: X × Ω → X and their iterates defined by f¹(x,ω) = f(x,ω₁), , and obtain theorems on the convergence (a.s. and in L¹) of the sequence (fⁿ(x,·)).