arXiv subjects
Publications and source records attributed to Leandro M. Del Pezzo.
The purpose of this work is to study a finite element method for finding solutions to the eigenvalue problem for the fractional Laplacian. We prove that the discrete eigenvalue problem converges to the continuous one and we show the order of such convergence. Finally, we perform some numerical experiments and compare our results with previous work by other authors.
In this paper we study the Dirichlet eigenvalue problem $$ -Δ_p u-Δ_{J,p}u =λ|u|^{p-2}u \quad \text{ in } Ω,\quad u=0 \quad\text{ in } Ω^c=\mathbb{R}^N\setminusΩ. $$ Here $Δ_p u$ is the standard local $p-$Laplacian, $Δ_{J,p}u$ is a nonlocal, $p-$homogeneous operator of order zero and $Ω$ is a bounded domain in $\mathbb{R}^N$. We show that the first eigenvalue (that is isolated and simple) satisfies $(λ_1)^{1/p}\to Λ$ as $p\to\infty$ where $Λ$ can be characterized in terms of the geometry of $Ω$. We also find that the eigenfunctions converge, $u_\infty=\lim_{p\to\infty} u_p$, and find the limit problem that is satisfied in the limit.
In this note we prove a trace theorem in fractional spaces with variable exponents. To be more precise, we show that if $p\colon\overlineΩ\times \overlineΩ\to (1,\infty)$ and $q:\partial Ω\rightarrow (1,\infty)$ are continuous functions such that \[ \frac{(n-1)p(x,x)}{n-sp(x,x)}>q(x) \qquad \mbox{in} \partial Ω\cap \{x\in\overlineΩ\colon n-sp(x,x) >0\}, \] then the inequality $$ \Vert f\Vert _{\scriptstyle L^{q(\cdot)}(\partial Ω)} \leq C \left\{\Vert f\Vert _{\scriptstyle L^{\bar{p}(\cdot)}(Ω)}+ [f]_{s,p(\cdot,\cdot)} \right\} $$ holds. Here $\bar{p}(x)=p(x,x)$ and $\lbrack f\rbrack_{s,p(\cdot,\cdot)} $ denotes the fractional seminorm with variable exponent, that is given by \[ \lbrack f\rbrack_{s,p(\cdot,\cdot)} := \inf \left\{λ>0\colon \int_Ω\int_Ω\frac{|f(x)-f(y)|^{p(x,y)}}{λ^{p(x,y)} |x-y|^{n+sp(x,y)}}dxdy<1\right\} \] and $\Vert f\Vert _{\scriptstyle L^{q(\cdot)}(\partial Ω)}$ and $\Vert f\Vert _{\scriptstyle L^{\bar{p}(\cdot)}(Ω)}$ are the usual Lebesgue norms with variable exponent.
Our propose here is to provide a Hopf Lemma and a strong minimum principle for week supersolutions of \[ (-Δ_p)^s u= c(x)|u|^{p-2}u \quad \text{ in } Ω\] where $Ω$ is an open set of $\mathbb{R}^N,$ $s\in(0,1),$ $p\in(1,+\infty),$ $c\in C(\overlineΩ)$ and $(-Δ_p)^s$ is the fractional $p$-Laplacian.
In this paper we extend two nowadays classical results to a nonlinear Dirichlet problem to equations involving the fractional $p-$Laplacian. The first result is a existence in a non-resonant range more specific between the first and second eigenvalue of the fractional $p-$Laplacian. The second result is the anti-maximum principle for the fractional $p-$Laplacian.
In this paper we analyze possible extensions of the classical Steklov eigenvalue problem to the fractional setting. In particular, we find a nonlocal eigenvalue problem of fractional type that approximate, when taking a suitable limit, the classical Steklov eigenvalue problem.
We study the eigenvalue problem for a system of fractional $p-$Laplacians, that is, $$ \begin{cases} (-Δ_p)^r u = λ\dfracαp|u|^{α-2}u|v|^β &\text{in } Ω,\vspace{.1cm} (-Δ_p)^s u = λ\dfracβp|u|^α|v|^{β-2}v &\text{in } Ω, u=v=0 &\text{in }Ω^c=\R^N\setminusΩ. \end{cases} $$ We show that there is a first (smallest) eigenvalue that is simple and has associated eigen-pairs composed of positive and bounded functions. Moreover, there is a sequence of eigenvalues $λ_n$ such that $λ_n\to\infty$ as $n\to\infty$. In addition, we study the limit as $p\to \infty$ of the first eigenvalue, $λ_{1,p}$, and we obtain $ [λ_{1,p}]^{\nicefrac{1}{p}}\to Λ_{1,\infty} $ as $p\to\infty,$ where $$ Λ_{1,\infty} = \inf_{(u,v)} \left\{ \frac{\max \{ [u]_{r,\infty} ; [v]_{s,\infty} \} }{ \| |u|^Γ |v|^{1-Γ} \|_{L^\infty (Ω)} } \right\} = \left[ \frac{1}{R(Ω)} \right]^{ (1-Γ) s + Γr }. $$ Here $R(Ω):=\max_{x\inΩ}\dist(x,\partialΩ)$ and $[w]_{t,\infty} \coloneqq \sup_{(x,y)\in\overlineΩ} \frac{| w(y) - w(x)|}{|x-y|^{t}}.$ Finally, we identify a PDE problem satisfied, in the viscosity sense, by any possible uniform limit along subsequences of the eigen-pairs.
We prove the existence of an unbounded branch of solutions to the non-linear non-local equation $$ (-Δ)^s_p u=λ|u|^{p-2}u + f(x,u,λ) \quad\text{in}\quad Ω,\quad u=0 \quad\text{in}\quad \mathbb{R}^n\setminusΩ, $$ bifurcating from the first eigenvalue. Here $(-Δ)^s_p$ denotes the fractional $p$-Laplacian and $Ω\subset\mathbb{R}^n$ is a bounded regular domain. The proof of the bifurcation results relies in computing the Leray--Schauder degree by making an homotopy respect to $s$ (the order of the fractional $p$-Laplacian) and then to use results of local case (that is $s=1$) found in [17]. Finally, we give some application to an existence result.
In this paper we study the eigenvalue problems for a nonlocal operator of order $s$ that is analogous to the local pseudo $p-$Laplacian. We show that there is a sequence of eigenvalues $λ_n \to \infty$ and that the first one is positive, simple, isolated and has a positive and bounded associated eigenfunction. For the first eigenvalue we also analyze the limits as $p\to \infty$ (obtaining a limit nonlocal eigenvalue problem analogous to the pseudo infinity Laplacian) and as $s\to 1^-$ (obtaining the first eigenvalue for a local operator of $p-$Laplacian type). To perform this study we have to introduce anisotropic fractional Sobolev spaces and prove some of their properties.
We deal with the first eigenvalue for a system of two $p-$Laplacians with Dirichlet and Neumann boundary conditions. If $Δ_{p}w=\mbox{div}(|\nabla w|^{p-2}w)$ stands for the $p-$Laplacian and $\fracα{p}+\fracβ{q}=1,$ we consider $$ \begin{cases} -Δ_pu= λα|u|^{α-2} u|v|^β &\text{ in }Ω,\\ -Δ_q v= λβ|u|^α|v|^{β-2}v &\text{ in }Ω,\\ \end{cases} $$ with mixed boundary conditions $$ u=0, \qquad |\nabla v|^{q-2}\dfrac{\partial v}{\partial ν}=0, \qquad \text{on }\partial Ω. $$ We show that there is a first non trivial eigenvalue that can be characterized by the variational minimization problem $$ λ_{p,q}^{α,β} = \min \left\{\dfrac{\displaystyle\int_Ω\dfrac{|\nabla u|^p}{p}\, dx +\int_Ω\dfrac{|\nabla v|^q}{q}\, dx} {\displaystyle\int_Ω |u|^α|v|^β\, dx} \colon (u,v)\in \mathcal{A}_{p,q}^{α,β}\right\}, $$ where $$ \mathcal{A}_{p,q}^{α,β}=\left\{(u,v)\in W^{1,p}_0(Ω)\times W^{1,q}(Ω)\colon uv\not\equiv0\text{ and }\int_Ω|u|^α|v|^{β-2}v \, dx=0\right\}. $$ We also study the limit of $λ_{p,q}^{α,β} $ as $p,q\to \infty$ assuming that $\fracα{p} \to Γ\in (0,1)$, and $ \frac{q}{p} \to Q \in (0,\infty)$ as $p,q\to \infty.$ We find that this limit problem interpolates between the pure Dirichlet and Neumann cases for a single equation when we take $Q=1$ and the limits $Γ\to 1$ and $Γ\to 0$.
In this work we study the asymptotic behavior of the first non-zero Neumann $p-$fractional eigenvalue $λ_1(s,p)$ as $s\to 1^-$ and as $p\to\infty.$ We show that there exists a constant $\mathcal{K}$ such that $\mathcal{K}(1-s)λ_1(s,p)$ goes to the first non-zero Neumann eigenvalue of the $p-$Laplacian. While in the limit case $p\to \infty,$ we prove that $λ_1(1,s)^{1/p}$ goes to an eigenvalue of the Hölder $\infty-$Laplacian.
We study the first eigenvalue of the $p-$Laplacian (with $1<p<\infty$) on a quantum graph with Dirichlet or Kirchoff boundary conditions on the nodes. We find lower and upper bounds for this eigenvalue when we prescribe the total sum of the lengths of the edges and the number of Dirichlet nodes of the graph. Also we find a formula for the shape derivative of the first eigenvalue (assuming that it is simple) when we perturb the graph by changing the length of an edge. Finally, we study in detail the limit cases $p\to \infty$ and $p\to 1$.
In this paper we give some estimates for nonlinear harmonic measures on trees. In particular, we estimate in terms of the size of a set $D$ the value at the origin of the solution to $ u(x)=F((x,0),\dots,(x,m-1))$ for every $x\in\mathbb{T}_m, $ a directed tree with $m$ branches with initial datum $f+χ_D$. Here $F$ is an averaging operator on $\mathbb{R}^m$, $x$ is a vertex of a directed tree $\mathbb{T}_m$ with regular $m$-branching and $(x,i)$ denotes a successor of that vertex for $0\le i\le m-1$.
We study evolution equations governed by an averaging operator on a directed tree, showing existence and uniqueness of solutions. In addition we find conditions of the initial condition that allows us to find the asymptotic decay rate of the solutions as $t\to \infty$. It turns out that this decay rate is not uniform, it strongly depends on how the initial condition goes to zero as one goes down in the tree.
In this paper we study the game $p-$Laplacian on a tree, that is, $$ u(x)=\fracα2\left\{\max_{y\in §(x)}u(y) + \min_{y\in §(x)}u(y)\right\} + \fracβ{m}\sum_{y\in §(x)} u(y), $$ here $x$ is a vertex of the tree and $S(x)$ is the set of successors of $x$. We study the family of the subsets of the tree that enjoy the unique continuation property, that is, subsets $U$ such that $u\mid_U=0$ implies $u \equiv 0$.
In this work, we study the rate of convergence of the finite element method for the $p(x)$Laplacian ($1< p_1\leq p(x)\leq p_2\leq 2$) in two dimensional convex domains.
In this paper we use probabilistic arguments (Tug-of-War games) to obtain existence of viscosity solutions to a parabolic problem of the form $$ {cases} K_{(x,t)}(D u)u_t (x,t)= \frac12 $.
In this paper we study the $H^2$ global regularity for solutions of the $p(x)-$Laplacian in two dimensional convex domains with Dirichlet boundary conditions. Here $p:Ω\to [p_1,\infty)$ with $p\in Lip(\barΩ)$ and $p_1>1$.