collaborators

7 papers

math.AP2025

Critical point localization and multiplicity results in Banach spaces via Nehari manifold technique

Radu Precup, Andrei Stan

In the paper, results on the existence of critical points in annular subsets of a cone are obtained with the additional goal of obtaining multiplicity results. Compared to other ap…

math.FA2025

Hybrid Nehari-Schauder type fixed point results and applications

Radu Precup, Andrei Stan

This paper develops a fixed point version of the well-known Nehari manifold method from critical point theory. The main result is formulated for systems of operator equations, rely…

math.AP2025

A Nehari manifold method for nonvariational problems

Radu Precup, Andrei Stan

The aim of this paper is to extend the Nehari manifold method from the variational setting to the nonvariational framework of fixed point equations. This is achieved by constructin…

math.FA2025

Two abstract methods of lower and upper solutions with applications

Andrei Stan

In this paper, we present two abstract methods for constructing a lower and an upper solution for a fixed point equation. The first method applies when the nonlinear operator is a…

math.OC2025

Control of semilinear differential equations with moving singularities

Radu Precup, Andrei Stan, Wei-Shih Du

In this paper, we present a control problem related to a semilinear differential equation with a moving singularity, i.e., the singular point depends on a parameter. The particular…

math.AP2025

Localization of critical points in annular conical sets via the method of Nehari manifold

Andrei Stan

Using the Nehari manifold method, we establish sufficient conditions such that a smooth functional attains a ground state within an annular domain of a closed cone. The localizatio…