Further applications of the Nehari manifold method to functionals in $C^1(X \setminus \{0\})$
Edir J. F. Leite, Humberto Ramos Quoirin, Kaye Silva
TL;DR
This work develops a two-point Nehari manifold framework for functionals in $C^1(X\setminus\{0\})$ whose fibering maps admit two critical points, producing ground-state and two unbounded sequences of critical values via restricted Ljusternik–Schnirelman theory. The authors establish the continuity of the fibering maps, the sphere-to-Nehari-homeomorphisms, and PS conditions on the restricted manifolds, yielding two families of critical values $\lambda_n^{+}$ and $\lambda_n^{-}$ with $\lambda_1^{+}$ as the ground state and $\lambda_n^{+}\le\lambda_n^{-}$; under extra hypotheses, they prove $\lambda_{n}^{+}<\lambda_{n}^{-}$ for all $n$. They apply the abstract results to prescribed energy problems and to the affine $p$-Laplacian with concave–convex nonlinearities, obtaining multiplicity results and detailed energy properties for small negative energy levels and small parameters $\lambda$. The paper thereby provides a robust, general variational framework for obtaining multiple solutions in nonstandard growth and nonlocal-type settings, including the affine operator context.
Abstract
We proceed with the study of the Nehari manifold method for functionals in $C^1(X \setminus \{0\})$, where $X$ is a Banach space. We deal now with functionals whose fibering maps have two critical points (a minimiser followed by a maximiser). Under some additional conditions we show that the Nehari manifold method provides us with the ground state level and two sequences of critical values for these functionals. These results are applied to the class of {\it prescribed energy problems} as well as to the concave-convex problem for the {\it affine} $p$-Laplacian operator.
