5 papers
Essential spectrum for the Laplacian
Lorenzo Brasco, Luca Briani, Giovanni Franzina
We introduce a variational notion of essential spectrum for the Dirichlet Laplacian. We then extend the classical Persson Theorem to this nonlinear setting. This result provide…
Low eigenvalues of the Laplacian in general open sets
Lorenzo Brasco, Luca Briani, Francesca Prinari
We consider the minmax Ljusternik-Schnirelmann levels of the constrained Dirichlet integral, on a general open set of the Euclidean space. We show that, whenever one of these l…
Extremals for sharp Poincaré-Sobolev inequalities: periodically perforated sets and beyond
Lorenzo Brasco, Luca Briani, Francesca Prinari
We consider periodically perforated unbounded open sets and prove existence of extremals for the relevant sharp Poincaré-Sobolev embedding constant. The existence result holds no…
Extremals for Poincaré-Sobolev sharp constants in Steiner symmetric sets
Lorenzo Brasco, Luca Briani, Francesca Prinari
We prove existence of minimizers for the sharp Poincaré-Sobolev constant in general Steiner symmetric sets, in the subcritical and superhomogeneous regime. The sets considered are…
Energy concentration in a two-dimensional magnetic skyrmion model: variational analysis of lattice and continuum theories
Luca Briani, Marco Cicalese, Leonard Kreutz
We investigate the formation of singularities in a baby Skyrme type energy model, which describes magnetic solitons in two-dimensional ferromagnetic systems. In presence of a diver…