arXiv subjects

Luigi Appolloni

Publications and source records attributed to Luigi Appolloni.

8 recordsLinked to original sources

arXiv2026

A logistic equation with non-local operators of order near zero

In this paper we study an equation driven by a non-local operator of order "near zero" with mixed Dirichlet-Neumann boundary conditions, modelling a biological system consisting of a population self-competing for resources in a closed environment and subject to an extremely heavy-tailed dispersal process. We establish several results concerning the existence of states in which the population can survive requiring different assumptions on the non-linear reaction term and on the various configurations of the sets where the Dirichlet or Neumann conditions hold.

math.AP↗

arXiv2025

Normalized Schrödinger equations with mass-supercritical nonlinearity in exterior domains

We consider the problem $-Δu+λu=u^{p-1}$, where $u\in H^1_0(Ω)$ verifies $\|u\|_{L^2}=m>0$, and $λ\in [0,+\infty)$. Here, $\mathbb{R}^N\setminusΩ$ is nonempty and compact. We prove the existence of a solution with a constrained Morse index lower than or equal to $N+1$, both in the case $m$ fixed and $\mathbb{R}^N\setminusΩ$ in a small ball and in the case $Ω$ fixed and $m$ large.

math.AP↗

arXiv2025

A Note on Moving Frames along Sobolev Maps and the Regularity of Weakly Harmonic Maps

The purpose of this note is twofold. First we show that, for weakly differentiable maps between Riemannian manifolds of any dimension, a smallness condition on a Morrey-norm of the gradient is sufficient to guarantee that the pulled-back tangent bundle is trivialised by a finite-energy frame over simply connected regions in the domain. This is achieved via new structure equations for a connection introduced by Rivière in the study of weakly harmonic maps, combined with Coulomb-frame methods and the Hardy-BMO duality of Fefferman-Stein. We also prove that for weakly harmonic maps from domains of any dimension into closed homogeneous targets, a smallness condition on the BMO seminorm of the map is sufficient to obtain full regularity.

math.AP↗

arXiv2023

A note on the NLS equation on Cartan-Hadamard manifolds with unbounded and vanishing potentials

We study the semilinear equation $-Δ_g u + V(σ) u = f(u)$ on a Cartan-Hadamard manifold ${\cal M}$ of dimension $N \geq 3$, and we prove the existence of a nontrivial solution under suitable assumptions on the potential function $V \in C({\cal M})$. In particular, the decay of $V$ at infinity is allowed, with some restrictions related to the geometry of ${\cal M}$. We generalize some results proved in $\mathbb{R}^N$ by Alves \emph{et al.}

math.AP↗

arXiv2022

Schrödinger equation on Cartan-Hadamard manifolds with oscillating nonlinearities

We study the equation $-Δ_g w+w=λα(σ) f(w)$ on a $d$-dimensional homogeneous Cartan-Hadamard Manifold $\mathcal{M}$ with $d \geq 3$. Without using the theory of topological indices, we prove the existence of infinitely many solutions for a class of nonlinearities $f$ which have an oscillating behavior either at zero or at infinity.

math.AP↗

arXiv2022

Multiple solutions for Schrödinger equations on Riemannian manifolds via $\nabla$-theorems

We consider a smooth, complete and non-compact Riemannian manifold $(\mathcal{M},g)$ of dimension $d \geq 3$, and we look for positive solutions to the semilinear elliptic equation $$ -Δ_g w + V w = αf(w) + λw \quad\hbox{in $\mathcal{M}$}. $$ The potential $V \colon \mathcal{M} \to \mathbb{R}$ is a continuous function which is coercive in a suitable sense, while the nonlinearity $f$ has a subcritical growth in the sense of Sobolev embeddings. By means of $\nabla$-Theorems introduced by Marino and Saccon, we prove that at least three solution exists as soon as the parameter $λ$ is sufficiently close to an eigenvalue of the operator $-Δ_g$.

math.AP↗

arXiv2021

On Critical Kirchhoff problems driven by the fractional Laplacian

We study a nonlocal parametric problem driven by the fractional Laplacian operator combined with a Kirchhoff-type coefficient and involving a critical nonlinearity term in the sense of Sobolev embeddings. Our approach is of variational and topological nature. The obtained results can be viewed as a nontrivial extension to the nonlocal setting of some recent contributions already present in the literature.

math.AP↗

arXiv2020

Normalized solutions for the fractional NLS with mass supercritical nonlinearity

We investigate the existence of solutions to the fractional nonlinear Schrödinger equation $(-Δ)^s u = f(u)$ with prescribed $L^2$-norm $\int_{\mathbb{R}^N} |u|^2 \, dx =m$ in the Sobolev space $H^s(\mathbb{R}^N)$. Under fairly general assumptions on the nonlinearity $f$, we prove the existence of a ground state solution and a multiplicity result in the radially symmetric case.

math.AP↗