On a theorem of Baire about lower semi-continuous functions
Abstract A theorem of Baire concerning the approximation of lower semicontinuous real valued functions defined on a metric space, by…
2008
Inequalities and approximation theory
Abstract The purpose of this paper is twofold. Firstly, we present an equivalence property involving isotonic linear functionals. Secondly, by…
On the iterates of a class of summation-type linear positive operators
AbstractThis note is focused upon positive linear operators which preserve the quadratic test function. By using contraction principle, we study…
On approximating operators preserving certain polynomials
Abstract The paper centers around a general class of discrete linear positive operators depending on a real parameter \(\alpha \geq…
On certain q-analogues of the Bernstein operators
Abstract In this note we study the limit of iterates of Lupas q-analogue of the Bernstein operators. Also, we introduce…
Nonresonance theory for semilinear operator equations under regularity conditions
AbstractA general nonresonance theory of semilinear operator equations under regularity conditions is developed. Existence of weak solutions (in the energetic…
Radial solutions for some classes of elliptic boundary value problems
Abstract The aim of this paper is to present some existence and localization results of radial solutions for elliptic equations…
Nonresonance and existence for systems of nonlinear operator equations
AbstractAn existence theory for systems of two non-linear operator equations in Hilbert spaces is presented under non-resonance conditions with respect…
Existence results for systems of nonlinear evolution equations
AbstractExistence results for semilinear systems of abstract evolution equations are established by means of Perov, Schauder and Leray-Schauder Fixed Point…
Positive solutions for elliptic boundary value problems with a Harnack-like property
Abstract The aim of this paper is to present some existence results of positive solutions for elliptic equations and systems…