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On a class of optimal partition problems related to the Fuč\'ık spectrum and to the monotonicity formulae

Monica Conti·Susanna Terracini·Gianmaria Verzini
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Abstract

In this paper we give an unified approach to some questions arising in different fields of nonlinear analysis, namely: (a) the study of the structure of the Fuč\'ık spectrum and (b) possible variants and extensions of the monotonicity formula by Alt--Caffarelli--Friedman \cite{acf}. In the first part of the paper we present a class of optimal partition problems involving the first eigenvalue of the Laplace operator. Beside establishing the existence of the optimal partition, we develop a theory for the extremality conditions and the regularity of minimizers. As a first application of this approach, we give a new variational characterization of the first curve of the Fuč\'ık spectrum for the Laplacian, promptly adapted to more general operators. In the second part we prove a monotonicity formula in the case of many subharmonic components and we give an extension to solutions of a class of reaction--diffusion equation, providing some Liouville--type theorems.

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Monica Conti, Susanna Terracini, Gianmaria Verzini. 2003-12-10. On a class of optimal partition problems related to the Fuč\'ık spectrum and to the monotonicity formulae. https://arxiv.org/abs/math/0312207

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