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Minimax Theory and its Applications 08 (2023), No. 2, 319--332 Copyright Heldermann Verlag 2023 Saddle Points of some Integral Functionals and Solutions of Elliptic Systems Lucio Boccardo Istituto Lombardo, Milano, Italy boccardo@mat.uniroma1.it Pasquale Imparato Roma, Italy pasquale.imparato1994@gmail.com Luigi Orsina Università La Sapienza, Roma, Italy orsina@mat.uniroma1.it [Abstract-pdf] \def\w{W_{0}^{1,2}(\Omega)} \def\wp{W_{0}^{1,p}(\Omega)} We prove the existence of finite energy solutions $u$ and $\psi$ for two systems, one of which is \begin{equation*} \left\{\ \begin{aligned} & u \in \w:\hskip8pt -{\rm div}\,(a(x)\,\nabla u) = -{\rm div}\,(\psi\,E(x))\,, \\[1mm] & \psi \in \wp:\ \ -{\rm div}\,(a(x)\,|\nabla\psi|^{p-2}\,\nabla\psi) + E(x) \cdot \nabla u = f(x)\,, \end{aligned} \right. \end{equation*} under some assumptions on $p$ and on the vector field $E(x)$. Keywords: Integral functions, saddle points, nonlinear elliptic equations. MSC: 35J20, 35J47, 35J62. [ Fulltext-pdf (124 KB)] for subscribers only. |