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Multiple solutions to relativistic systems with potential boundary conditions

Published online by Cambridge University Press:  01 September 2025

Petru Jebelean
Affiliation:
Institute for Advanced Environmental Research, West University of Timişoara, Blvd. V. Pârvan, Timişoara, Romania
Călin Șerban*
Affiliation:
Department of Mathematics, West University of Timişoara, Blvd. V. Pârvan, Timişoara, Romania
Stepan Tersian
Affiliation:
Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Sofia, Bulgaria
*
Corresponding author: Călin Șerban, email: calin.serban@e-uvt.ro

Abstract

We consider potential systems of differential equations of the form

\begin{equation*}-\left[ \phi(u^{\prime}) \right] ^{\prime} = \nabla_u F(t,u),\quad \mbox{in } [0,T],\end{equation*}
under the general boundary condition
\begin{equation*}\left ( \phi \left( u^{\prime }\right)(0), -\phi \left( u^{\prime }\right)(T)\right )\in \partial j(u(0), u(T)),\end{equation*}
where $\phi(y)={y}/{\sqrt{1- |y|^2}}$ and $j:\mathbb{R}^N \times \mathbb{R}^N \rightarrow (-\infty, +\infty]$ is convex and lower semicontinuous. Making use of the variational approach introduced in the recent paper “Potential systems with singular $\phi$-Laplacian”, we obtain multiplicity of solutions when the action functional is even, as well as existence of multiple geometrically distinct solutions when this functional is invariant with respect to some discrete group.

Information

Type
Research Article
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of The Edinburgh Mathematical Society.

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