45 citations · 133 across the 45 of their papers we have counts for
6 papers · 1 filter
Spectral flow, Brouwer degree and Hill's determinant formula
Alessandro Portaluri, Li Wu
In 2005 a new topological invariant defined in terms of the Brouwer degree of a determinant map, was introduced by Musso, Pejsachowicz and the first name author for counting the co…
A Multiplicity result for a class of strongly indefinite asymptotically linear second order systems
Anna Capietto, Francesca Dalbono, Alessandro Portaluri
We prove a multiplicity result for a class of strongly indefinite nonlinear second order asymptotically linear systems with Dirichlet boundary conditions. The key idea for the proo…
A -theoretical invariant and bifurcation for a parameterized family of functionals
Alessandro Portaluri
For a family of functionals defined on a Hilbert manifold and smoothly depending on a compact finite dimensional manifold, we give a sufficient condition on the parameter space in…
Brief communication. An indefinite Sturm theory
Alessandro Portaluri
Sturm theory for second order differential equations was generalized to systems and higher order equations with positive leading coefficient by several authors. Here we propose a S…
On a generalized Sturm theorem
Alessandro Portaluri
Sturm oscillation theorem for second order differential equations was generalized to systems and higher order equations with positive leading coefficient by several authors. What w…
A bifurcation result for semi-Riemannian trajectories of the Lorentz force equation
Paolo Piccione, Alessandro Portaluri
By decision of the first author, the paper will no longer be available.