arXiv subjects
Publications and source records attributed to Laurent Véron.
We study the local properties of positive solutions of the equation $-Δu+ m\abs{\nabla u}^q-e^{u}=0$ in a punctured domain $Ω\setminus\{0\}$ of $R^N$, $N\geq 2$, where $m$ is a positive parameter and $q>1$. We study particularly the existence of solutions with an isolated singularity and the local behaviour of such singular solutions. .
We study some local and global properties of solutions of $-Δu- m\abs{\nabla u}^q-e^{u}=0$ in a punctured domain $Ω\setminus\{0\}$, or in an exterior domain of $R^N$, $N\geq 2$, where $m$ is a positive parameter and $q>1$. We study particularly the local behaviour of solutions with an isolated singularity or the asymptotic behaviour for solutions defined in an exterior domain, and also the existence of solutions with the behaviours previously described. These behaviours change drastically according $q$ is smaller or larger than $2$. Many results are obtained by introducing various dynamical systems associated to the equation.
We study the local properties of positive solutions of the equation -Delta u= exp(u) in a punctured domain Omega of RN in the range of parameters q > 1 and M > 0. We prove a series of a priori estimates near a singular point. In the case of radial solutions we use various techniques inherited from the dynamical systems theory to obtain the precise behaviour of singular solutions. We prove also the existence of singular solutions with these precise behaviours.
We study the local properties of positive solutions of the equation $-Δu+ae^{bu}=m|\nabla u|^q$ in a punctured domain $Ω\setminus\{0\}$ of $\bf R^2$ where $m,a,b$ are positive parameters and $q>1$. We study particularly the existence of solutions with an isolated singularity and the local behaviour of such singular solutions.
Let $\lnlap$ be the logarithmic Laplacian operator with Fourier symbol $2\ln |ζ|$, we study the expression of the diffusion kernel which is associated to the equation $$\partial_tu+ \lnlap u=0 \ \ {\rm in}\ \, (0,\tfrac N2) \times \R^N,\quad\quad u(0,\cdot)=0\ \ {\rm in}\ \, \R^N\setminus \{0\}.$$ We apply our results to give a classification of the solutions of $$\left\{ \arraycolsep=1pt \begin{array}{lll} \displaystyle \partial_tu+ \lnlap u=0\quad \ &{\rm in}\ \ (0,T)\times \R^N\\[2.5mm] \phantom{ \lnlap \ \, } \displaystyle u(0,\cdot)=f\quad \ &{\rm{in}}\ \ \R^N \end{array} \right. $$ and obtain an expression of the fundamental solution of the associated stationary equation in $\R^N$, and of the fundamental solution in a bounded domain, i.e. $$\lnlap u=kδ_0\quad {\rm in}\ \ \cD'(Ω)\quad \text{such that }\,u=0\quad {\rm in}\ \ \R^N\setminusΩ. $$
We study the local properties of positive solutions of the equation $-Δu=u^p-m|\nabla u|^q$ in a punctured domain $Ω\setminus\{0\}$ of $\mathbb{R}^N$ or in a exterior domain $\mathbb{R}^N\setminus B_{r_0}$ in the range $\min\{p,q\}>1$ and $m>0$. We prove a series of a priori estimates depending $p$ and $q$, and of the sign of $q-\frac {2p}{p+1}$ and $q-p$. Using various techniques we obtain removability results for singular sets and we give a precise description of behaviour of solutions near an isolated singularity or at infinity in $\mathbb{R}^N$.
We study the isolated singularities of functions satisfying (E) (--$Δ$) s v$\pm$|v| p--1 v = 0 in $Ω$\{0}, v = 0 in R N \$Ω$, where 0 < s < 1, p > 1 and $Ω$ is a bounded domain containing the origin. We use the Caffarelli-Silvestre extension to R + x R N. We emphasize the obtention of a priori estimates, analyse the set of self-similar solutions via energy methods to characterize the singularities.
We study properties of positive functions satisfying (E) --$Δ$u+m|$\nabla$u| q -- u p = 0 is a domain $Ω$ or in R N + when p > 1 and 1 < q < 2. We give sufficient conditions for the existence of a solution to (E) with a nonnegative measure $μ$ as boundary data, and these conditions are expressed in terms of Bessel capacities on the boundary. We also study removable boundary singularities and solutions with an isolated singularity on $\partial$$Ω$. The different results depends on two critical exponents for p = p c := N +1 N --1 and for q = q c := N +1 N and on the position of q with respect to 2p p+1. Contents
We study properties of nonnegative functions satisfying (E)$\;-Δu+u^p-M|\nabla u|^q=0$ is a domain of $\mathbb{R}^N$ when $p>1$, $M>0$ and $1<q<p$. We concentrate our analysis on the solutions of (E) with an isolated singularity, or in an exterior domain, or in the whole space. The existence of such solutions and their behaviours depend strongly on the values of the exponents $p$ and $q$ and in particular according to the sign of $q-\frac{2p}{p+1}$, and when $q=\frac{2p}{p+1}$, also on the value of the parameter $M$ which becomes a key element. The description of the different behaviours is made possible by a sharp analysis of the radial solutions of (E).
We study nonlinear systems of the form $-Δ\_pu=v^{q\_1}+μ,\;-Δ\_pv=u^{q\_2}+η$ and $F\_k[-u]=v^{s\_1}+μ,\;F\_k[-v]=u^{s\_2}+η$ in a bounded domain $Ω$ or in $\mathbb{R}^N$ where $μ$ and $η$ are nonnegative Radon measures, $Δ\_p$ and $F\_k$ are respectively the $p$-Laplacian and the $k$-Hessian operators and $q\_1$, $q\_2$, $s\_1$ and $s\_2$ positive numbers. We give necessary and sufficient conditions for existence expressed in terms of Riesz or Bessel capacities.
We study the existence of separable infinite harmonic functions in any cone of R N vanishing on its boundary under the form u(r, $σ$) = r --$β$ $ω$($σ$). We prove that such solutions exist, the spherical part $ω$ satisfies a nonlinear eigenvalue problem on a subdomain of the sphere S N --1 and that the exponents $β$ = $β$ + > 0 and $β$ = $β$ -- < 0 are uniquely determined if the domain is smooth.
We prove the existence of p-harmonic functions under the form u(r, $σ$) = r --$β$ $ω$($σ$) in any cone C S generated by a spherical domain S and vanishing on $\partial$C S. We prove the uniqueness of the exponent $β$ and of the normalized function $ω$ under a Lipschitz condition on S.
We study the boundary behaviour of the solutions of (E) $-Δ_p u+|\nabla u|^q=0$ in a domain $Ω\subset \mathbb{R}^N$, when $N\geq p > q >p-1$. We show the existence of a critical exponent $q_* < p$ such that if $p-1 < q < q_*$ there exist positive solutions of (E) with an isolated singularity on $\partialΩ$ and that these solutions belong to two different classes of singular solutions. If $q_*\leq q < p$ no such solution exists and actually any boundary isolated singularity of a positive solution of (E) is removable. We prove that all the singular positive solutions are classified according the two types of singular solutions that we have constructed.
We study the admissible growth at infinity of initial data of positive solutions of $\prt\_t u-\Gd u+f(u)=0$ in $\BBR\_+\ti\BBR^N$ when $f(u)$ is a continuous function, {\it mildly} superlinear at infinity, the model case being $f(u)=u\ln^\ga (1+u)$ with $1\textless{}\ga\textless{}2$. We prove in particular that if the growth of the initial data at infinity is too strong, there is no more diffusion and the corresponding solution satisfies the ODE problem $\prt\_t \gf+f(\gf)=0$ on $\BBR\_+$ with $\gf(0)=\infty$.
We give new criteria for the existence of weak solutions to an equation with a super linear source term \begin{align*}-Δu = u^q ~~\text{in}~Ω,~~u=σ~~\text{on }~\partialΩ\end{align*}where $Ω$ is a either a bounded smooth domain or $\mathbb{R}\_+^{N}$, $q\textgreater{}1$ and $σ\in \mathfrak{M}^+(\partialΩ)$ is a nonnegative Radon measure on $\partialΩ$. One of the criteria we obtain is expressed in terms of some Bessel capacities on $\partialΩ$. We also give a sufficient condition for the existence of weak solutions to equation with source mixed terms. \begin{align*} -Δu = |u|^{q\_1-1}u|\nabla u|^{q\_2} ~~\text{in}~Ω,~~u=σ~~\text{on }~\partialΩ\end{align*} where $q\_1,q\_2\geq 0, q\_1+q\_2\textgreater{}1, q\_2\textless{}2$, $σ\in \mathfrak{M}(\partialΩ)$ is a Radon measure on $\partialΩ$.
In this article, we study the existence of positive solutions to elliptic equation (E1) $$(-Δ)^αu=g(u)+σν\quad{\rm in}\quad Ω,$$ subject to the condition (E2) $$u=\varrhoμ\quad {\rm on}\quad \partialΩ \ {\rm if}\ α=1\qquad {\rm or\ \ in}\ \ Ω^c \ \ {\rm if}\ α\in(0,1),$$ where $σ,\varrho\ge0$, $Ω$ is an open bounded $C^2$ domain in $\mathbb{R}^N$, $(-Δ)^α$ denotes the fractional Laplacian with $α\in(0,1)$ or Laplacian operator if $α=1$, $ν,μ$ are suitable Radon measures and $g:\mathbb{R}_+\mapsto\mathbb{R}_+$ is a continuous function. We introduce an approach to obtain weak solutions for problem (E1)-(E2) when $g$ is integral subcritical and $σ,\varrho\ge0$ small enough.