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Leandro M. Del Pezzo

Publications and source records attributed to Leandro M. Del Pezzo.

At least 19 recordsLinked to original sources
arXiv2026

Interior Regularity of Mixed Local-Nonlocal Parabolic Semilinear Equations

In this paper we prove the existence, uniqueness and regularity of classical solutions \break of a semilinear parabolic equation with a mixed local and nonlocal diffusion operator \break $\mathcal{L} = -(-Δ)^s + Δ$ and Dirichlet boundary conditions. Here, $(-Δ)^s$ is the integral fractional laplacian and $Δ$ is the classic local laplacian. We then study the interior regularity of said solutions and conclude that they are Hölder continuous in both space and time, and they are $C^{2,α}_{loc}$ in space for all positive times.

math.AP↗
arXiv2026

A method of moving planes for a mixed local-nonlocal parabolic system with quenching

In this paper we develop a parabolic version of the method of moving planes on systems with a mixed local and nonlocal diffusion operator, that being $\mathcal{L} = -(-Δ)^s + Δ$, where $(-Δ)^s$ is the integral fractional laplacian. We then use this result to study the quenching phenomena occurring in said systems with a singular absorption term of the type $(1-u)^{-p}$. We prove that there exists a range of multiplicative parameters for which every solution presents quenching, and that for any initial datum $u_0$, there exists a small enough multiplicative parameter such as the solution is globally defined. We also prove that the quenching phenomena cannot happen arbitrarily close to the boundary, but they are contained in a compact subset of the domain.

math.AP↗
arXiv2026

The evolution equation and the eigenvalue problem for the Laplacian in a regular tree

In this paper, our main goal is to study the evolution problem associated with the Laplacian operator with Dirichlet boundary conditions on a regular tree. To this end, we place special emphasis on the associated first eigenvalue problem, which provides the fundamental tool for describing the long-time dynamics. First, we prove existence and uniqueness of solutions when the initial condition is compatible with the boundary condition. Next, we address the asymptotic behavior of the solutions and show that they decay to zero exponentially fast. This decay rate is determined by the associated first eigenvalue, which we also analyze in detail.

math.AP↗
arXiv2026

Besov regularity of solutions to the Dirichlet problem for the Bessel $(p,s)$-Laplacian

We study the Dirichlet problem for a class of fractional $p$-Laplacian operators of order $s \in (0,1)$ defined through the Riesz fractional gradient, which differs fundamentally from the standard fractional $p$-Laplacian. Our analysis combines the framework of Lions-Calderón spaces, Besov embeddings, and an adaptation of Nirenberg's difference quotient method, originally developed by Savaré, to the fractional Riesz setting. As a main result, we establish global Besov regularity estimates for weak solutions. Concretely, in the superquadratic regime $p \geq 2$, we prove $u \in \dot{B}_{p,\infty}^{s+1/p}(Ω)$ for $s \in [\frac{1}{p'},1)$, and $u \in \dot{B}_{p,\infty}^{s+\frac{s}{p-1}}(Ω)$ for $s \in (0,\frac{1}{p'})$. In the subquadratic case $1<p<2$, we show $u \in \dot{B}_{p,\infty}^{s+1/2}(Ω)$ for $s \in [\frac{1}{2},1)$, and $u \in \dot{B}_{p,\infty}^{2s}(Ω)$ for $s \in (0,\frac12)$, with quantitative bounds depending on the source data.

math.AP↗
arXiv2025

Mixed local and nonlocal laplacian without standard critical exponent for Lane-Emden equation

In this paper, we investigate a mixed elliptic equation involving both local and nonlocal Laplacian operators, with a power-type nonlinearity. Specifically, we consider a Lane-Emden type equation of the form \[-Δu + (-Δ)^s u = u^p,\quad\mbox{ in }\mathbb{R}^n.\] where the operator combines the classical Laplacian and the fractional Laplacian. We establish the existence of solutions for exponents slightly below the critical local Sobolev exponent, that is, for $p < \frac{n+2}{n-2}$, with $p$ close to $\frac{n+2}{n-2}$. Our results show that, due to the interaction between the local and nonlocal operators, this mixed Lane-Emden-Fowler equation does not admit a critical exponent in the traditional sense. The existence proof is carried out using a Lyapunov-Schmidt type reduction method and, as far as we know, provide the first example of an elliptic operator for which the duality between critical exponents fails.

math.AP↗
arXiv2025

The fundamental solution of the fractional p-laplacian

In this article, we find the fundamental solution of the fractional p-laplacian and use them to prove two different Liouville-type theorems. A non-existence classical Liouville-type theorem for p-superharmonic and a Louville type results for an Emden-Folder type equation with the fractional p-laplacian.

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arXiv2024

The limit as $s\nearrow 1$ of the fractional convex envelope

We study the behavior of the fractional convexity when the fractional parameter goes to 1. For any notion of convexity, the convex envelope of a datum prescribed on the boundary of a domain is defined as the largest possible convex function inside the domain that is below the datum on the boundary. Here we prove that the fractional convex envelope inside a strictly convex domain of a continuous and bounded exterior datum converges when $s\nearrow 1$ to the classical convex envelope of the restriction to the boundary of the exterior datum.

math.AP↗
arXiv2024

Quasiconvex functions on regular trees

We introduce a definition of a quasiconvex function on an infinite directed regular tree that depends on what we understood by a segment on the tree. Our definition is based on thinking on segments as sub-trees with the root as the midpoint of the segment. A convex set in the tree is then a subset such that it contains every midpoint of every segment with terminal nodes in the set. Then a quasiconvex function is a real map on the tree such that every level set is a convex set. For this concept of quasiconvex functions on a tree, we show that given a continuous boundary datum there exists a unique quasiconvex envelope on the tree and we characterize the equation that this envelope satisfies. It turns out that this equation is a mean value property that involves a median among values of the function on successors of a given vertex. We also relate the quasiconvex envelope of a function defined inside the tree with the solution of an obstacle problem for this characteristic equation.

math.AP↗
arXiv2024

The evolution problem associated with the fractional first eigenvalue

In this paper we study the evolution problem associated with the first fractional eigenvalue. We prove that the Dirichlet problem with homogeneous boundary condition is well posed for this operator in the framework of viscosity solutions (the problem has existence and uniqueness of a solution and a comparison principle holds). In addition, we show that solutions decay to zero exponentially fast as $t\to \infty$ with a bound that is given by the first eigenvalue for this problem that we also study.

math.AP↗
arXiv2022

Non-simultaneous blow-up for a system with local and non-local diffusion

We study the possibility of non-simultaneous blow-up for positive solutions of a coupled system of two semilinear equations, $u_t = J*u-u+ u^αv^p$, $v_t =Δv^+u^qv^β$, $p, q, α, β>0$ with homogeneous Dirichlet boundary conditions and positive initial data. We also give the blow-up rates for non-simultaneous blow-up.

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arXiv2021

Weak and viscosity solutions for non-homogeneous fractional equations in Orlicz spaces

In this paper, we consider non-homogeneous fractional equations in Orlicz spaces, with a source depending on the spatial variable, the unknown function, and its fractional gradient. The latter is adapted to the Orlicz framework. The main contribution of the article is to establish the equivalence between weak and viscosity solutions for such equations.

math.AP↗
arXiv2021

Fractional convexity

We introduce a notion of fractional convexity that extends naturally the usual notion of convexity in the Euclidean space to a fractional setting. With this notion of fractional convexity, we study the fractional convex envelope inside a domain of an exterior datum (the largest possible fractional convex function inside the domain that is below the datum outside) and show that the fractional convex envelope is characterized as a viscosity solution to a non-local equation that is given by the infimum among all possible directions of the $1-$dimensional fractional Laplacian. For this equation we prove existence, uniqueness and a comparison principle (in the framework of viscosity solutions). In addition, we find that solutions to the equation for the convex envelope are related to solutions to the fractional Monge-Ampere equation.

math.AP↗
arXiv2021

Convex and quasiconvex functions in metric graphs

We study convex and quasiconvex functions on a metric graph. Given a set of points in the metric graph, we consider the largest convex function below the prescribed datum. We characterize this largest convex function as the unique largest viscosity subsolution to a simple differential equation, $u''=0$ on the edges, plus nonlinear transmission conditions at the vertices. We also study the analogous problem for quasiconvex functions and obtain a characterization of the largest quasiconvex function that is below a given datum.

math-ph↗
arXiv2019

Convex envelopes on Trees

We introduce two notions of convexity for an infinite regular tree. For these two notions we show that given a continuous boundary datum there exists a unique convex envelope on the tree and characterize the equation that this envelope satisfies. We also relate the equation with two versions of the Laplacian on the tree. Moreover, for a function defined on the tree, the convex envelope turns out to be the solution to the obstacle problem for this equation.

math.AP↗
arXiv2019

Dirichlet-to-Neumann maps on Trees

In this paper we study the Dirichlet-to-Neumann map for solutions to mean value formulas on trees. We give two alternative definition of the Dirichlet-to-Neumann map. For the first definition (that involves the product of a "gradient" with a "normal vector" and for a linear mean value formula on the directed tree (taking into account only the successors of a given node) we obtain that the Dirichlet-to-Neumann map is given by $g\mapsto cg'$ (here $c$ is an explicit constant). Notice that this is a local operator of order one. We also consider linear undirected mean value formulas (taking into account not only the successors but the ancestor and the successors of a given node) and prove a similar result. For this kind of mean value formula we include some existence and uniqueness results for the associated Dirichlet problem. Finally, we give an alternative definition of the Dirichlet-to-Neumann map (taking into account differences along a given branch of the tree). With this alternative definition, for a certain range of parameters, we obtain that the Dirichlet-to-Neumann map is given by a nonlocal operator (as happens for the classical Laplacian in the Euclidean space).

math.AP↗
arXiv2019

Spectrum of the fractional $p-$Laplacian in $\mathbb{R}^N$ and decay estimate for positive solutions of a Schrödinger equation

In this paper, we prove the existence of unbounded sequence of eigenvalues for the fractional $p-$Laplacian with weight in $\mathbb{R}^N.$ We also show a nonexistence result when the weighthas positive integral. In addition, we show some qualitative properties of the first eigenfunction including a sharp decay estimate. Finally, we extend the decay result to the positive solutions of a Schrödinger type equation.

math.AP↗
arXiv2018

An optimization problem with volume constraint with applications to optimal mass transport

In this manuscript we study the following optimization problem with volume constraint: \[ \min\left\{\frac{1}{p}\int_Ω |\nabla v|^pdx- \int_{\partial Ω} gv\,dS \colon v \in W^{1, p} \left(Ω\right), \text{ and } |\{v>0\}| \leq α\right\}. \] Here $g$ is acontinuous function and $α$ is a fixed constant such that $0< α< |Ω|$. Under the assumption that $\displaystyle \int_{\partial Ω} g(x)dS >0$ we prove that a minimizer exists and satisfies $$ \left\{ \begin{array}{ccl} -Δ_p u_p = 0 &\text{in } &\{u_p>0\} \cup \{u_p<0\}, \\[5pt] |\nabla u_p|^{p-2}\frac{\partial u_p}{\partial ν} = g & \text{on } &\partial Ω \cap\partial(\{u_p>0\} \cup \{u_p<0\} ) ,\\[5pt] |\{u_p>0\}| = α. & & \end{array} \right. $$ Next, we analyze the limit as $p\to \infty$. We obtain that any sequence of weak solutions converges, up to a subsequence, $\lim\limits_{p_j \to \infty} u_{p_j}(x)=u_{\infty}(x)$, uniformly in $\overlineΩ$, and uniform limits, $u_\infty$, are solutions to the maximization problem with volume constraint $$ \max\left\{ \int_{\partial Ω} gv\,dS \colon v \in W^{1, \infty} \left(Ω\right), \|\nabla v\|_{L^{\infty}(Ω)}\leq 1 \text{ and }|\{v>0\}| \leq α\right\}. $$ Furthermore, we obtain the limit equation that is verified by $u_\infty$ in the viscosity sense. Finally, it turns out that such a limit variational problem is connected to the Monge-Kantorovich mass transfer problem with the involved measures are supported on $\partial Ω$ and along the limiting free boundary, $\partial \{u_{\infty} \neq 0\}$.

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