activity
20132026
collaborators

14 papers

math.AP2026

Geometrically distinct unbounded continua of solutions for Yamabe-type equations

Piotr Stefaniak

We study global bifurcation for Yamabe-type equations on closed Riemannian manifolds with symmetries. For isometric group actions with interval orbit space and a suitable range of…

math.DS2025

Periodic solutions of autonomous -symmetric Newtonian systems

A. Golebiewska, S. Rybicki, P. Stefaniak

The aim of this paper is to formulate necessary conditions and sufficient ones for the existence of closed connected sets of nonstationary -periodic solutions of -symmetr…

math.AP2025

Global bifurcation of solutions to elliptic systems with system and domain symmetries

Piotr Stefaniak

We study parameterized elliptic systems on symmetric domains with additional system symmetries. We prove the existence of continua of nontrivial solutions bifurcating from the cons…

math.AP2025

Wavelet based solutions to the Poisson and the Helmholtz equations on the -dimensional unit sphere

Ilona Iglewska-Nowak, Piotr Stefaniak

We present a method of solving partial differential equations on the -dimensional unit sphere using methods based on the continuous wavelet transform derived from approximate id…

math.AP2025

Unbounded sets of solutions of non-cooperative elliptic systems on symmetric spaces

Piotr Stefaniak

The aim of this paper is to show that, for a class of non-cooperative elliptic systems on compact symmetric spaces, any continuum of nontrivial solutions bifurcating from the set o…

math.DS2021

Periodic solutions to symmetric Newtonian systems in neighborhoods of orbits of equilibria

Anna Gołębiewska, Marta Kowalczyk, Sławomir Rybicki +1

The aim of this paper is to prove the existence of periodic solutions to symmetric Newtonian systems in any neighborhood of an isolated orbit of equilibria. Applying equivariant bi…

math-ph2021

Wavelet methods in partial differential equations on spheres

{Ilona Iglewska-Nowak, Piotr Stefaniak

We propose a method of solving partial differential equations on the -dimen\-sional unit sphere with methods based on the continuous wavelet transform derived from approximate i…

math.AP2021

Bifurcations from degenerate orbits of solutions of nonlinear elliptic systems

Anna Gołębiewska, Joanna Kluczenko, Piotr Stefaniak

The aim of this paper is to study global bifurcations of non-constant solutions of some nonlinear elliptic systems, namely the system on a sphere and the Neumann problem on a ball.…

math.AP2020

Structure of sets of solutions of parametrised semi-linear elliptic systems on spheres

Anna Gołębiewska, Piotr Stefaniak

In this paper we study a parametrised non-cooperative symmetric semi-linear elliptic system on a sphere. Assuming that there exist critical orbits of the potential, we study the st…

math.AP2019

Connected sets of solutions of symmetric elliptic systems

Anna Gołębiewska, Sławomir Rybicki, Piotr Stefaniak

The purpose of this paper is twofold. First we study bifurcations of connected sets of critical orbits of some invariant functional from a given family of critical orbits. We use t…

math.AP2018

Global bifurcation index of critical orbit of strongly indefinite functional

Anna Gołębiewska, Piotr Stefaniak

In this paper we study an index of a critical orbit, defined in terms of the degree for invariant strongly indefinite functionals. We establish a relationship of this index with th…

math.AP2017

Bifurcations from the orbit of solutions of the Neumann problem

Anna Gołębiewska, Joanna Kluczenko, Piotr Stefaniak

The purpose of this paper is to study weak solutions of a nonlinear Neumann problem considered on a ball. Assuming that the potential is invariant, we consider an orbit of critical…

math.AP2017

Rabinowitz alternative for non-cooperative elliptic systems on geodesic balls

Sławomir Rybicki, Naoki Shioji, Piotr Stefaniak

The purpose of this paper is to study properties of continua (closed connected sets) of nontrivial solutions of non-cooperative elliptic systems considered on geodesic balls in $S^…

math.AP2013

Symmetry breaking of solutions of non-cooperative elliptic systems

Piotr Stefaniak

In this article we study the symmetry breaking phenomenon of solutions of noncooperative elliptic systems. We apply the degree for G-invariant strongly indefinite functionals to ob…