We prove that parameter-elliptic extensions of cone differential operators have a bounded $H_\infty$-calculus. Applications concern the Laplacian and the porous medium equation on manifolds with warped conical singularities.
On a manifold $X$ with boundary and bounded geometry we consider a strongly elliptic second order operator $A$ together with a degenerate boundary operator $T$ of the form $T=φ_0γ_0 + φ_1γ_1$. Here $γ_0$ and $γ_1$ denote the evaluation of a function and its exterior normal derivative, respectively, at the boundary. We assume that $φ_0,φ_1\in C^{\infty}_b(\partial X)$, $φ_0,φ_1\ge 0$, and $φ_0+φ_1\geq c$, for some $c>0$. We also assume that the highest order coefficients of $A$ belong to $C^τ(X)$ for some $τ>0$ and the lower order coefficients are in $L_\infty(X)$. We show that the $L_p(X)$-rea…
Realizations of differential operators subject to differential boundary conditions on manifolds with conical singularities are shown to have a bounded $H_{\infty}$-calculus in appropriate $L_{p}$-Sobolev spaces provided suitable conditions of parameter-ellipticity are satisfied. Applications concern the Dirichlet and Neumann Laplacian and the porous medium equation.
We show that for any regular bounded domain $Ω\subseteq \mathbb R^n$, $n=2,3$, there exist infinitely many global diffeomorphisms equal to the identity on $\partial Ω$ which solve the Eikonal equation. We also provide explicit examples of such maps on annular domains. This implies that the $\infty$-Laplace system arising in vectorial Calculus of Variations in $L^\infty$ does not suffice to characterise either limits of $p$-Harmonic maps as $p\to \infty$, or absolute minimisers in the sense of Aronsson.
The purpose of these expository notes is to give a quick and elementary, yet rigorous, presentation of the rudiments of the theory of Viscosity Solutions for fully nonlinear 2nd order PDE, with applications to Calculus of Variations in the space $L^\infty$.
We consider a smooth, compact and embedded hypersurface $Σ$ without boundary and show that the corresponding (shifted) surface Stokes operator $ω+A_{S,Σ}$ admits a bounded $H^\infty$-calculus with angle smaller than $π/2$, provided $ω>0$. As an application, we consider critical spaces for the Navier-Stokes equations on the surface $Σ$. In case $Σ$ is two-dimensional, we show that any solution with a divergence-free initial value in $L_2(Σ,\mathsf{T}Σ)$ exists globally and converges exponentially fast to an equilibrium, that is, to a Killing field.
For $\mathrm{H} \in C^2(\mathbb{R}^{N \times n})$ and $u : Ω\subseteq \mathbb{R}^n \to \mathbb{R}^N$, consider the system \[ \label{1}\mathrm{A}\_\infty u\, :=\,\Big(\mathrm{H}\_P \otimes \mathrm{H}\_P + \mathrm{H}[\mathrm{H}\_P]^\bot \mathrm{H}\_{PP}\Big)(\mathrm{D} u): \mathrm{D}^2 u\, =\,0. \tag{1}\]We construct $\mathcal{D}$-solutions to the Dirichlet problem for (1), an apt notion of generalised solutions recently proposed for fully nonlinear systems. Our $\mathcal{D}$-solutions are $W^{1,\infty}$-submersions and are obtained without any convexity hypotheses for $\mathrm{H}$, through a re…
An introduction to the vectorial Calculus of Variations in $\textbf{L}^\infty$ AND Aronsson PDE systems
Department of Physics, College of Education for Pure Sciences, University of Kerbala(卡尔巴拉大学纯科学学院教育学院物理系);Department of Mathematics and Statistics, University of Reading(雷丁大学数学与统计系)
In this paper we consider the Laplace operator with Dirichlet boundary conditions on a smooth domain. We prove that it has a bounded $H^\infty$-calculus on weighted $L^p$-spaces for power weights which fall outside the classical class of $A_p$-weights. Furthermore, we characterize the domain of the operator and derive several consequences on elliptic and parabolic regularity. In particular, we obtain a new maximal regularity result for the heat equation with rough inhomogeneous boundary data.
Let $n,N\in \mathbb{N}$ with $Ω\subseteq \mathbb{R}^n$ open. Given $H \in C^2(Ω\times \mathbb{R}^N\times \mathbb{R}^{Nn}),$ we consider the functional \[ \tag{1} \label{1} E_\infty (u,\mathcal{O})\, :=\, \underset{\mathcal{O}}{\mathrm{ess}\,\sup}\, H (\cdot,u,\mathrm{D} u) ,\ \ \ u\in W^{1,\infty}_\text{loc}(Ω,\mathbb{R}^N),\ \ \ \mathcal{O} \Subset Ω. \] The associated PDE system which plays the role of Euler-Lagrange equations in $L^\infty$ is \[ \label{2} \tag{2} \left\{ \begin{array}{r} H_{P}(\cdot, u, \mathrm{D}u)\, \mathrm{D} \big(H(\cdot, u, \mathrm{D} u)\big) \, = \, 0, \ \ \ H(\cdot, …
We establish pathwise continuity properties of solutions to a stochastic Volterra equation with an additive noise term given by a local martingale. The deterministic part is governed by an operator with an $H^\infty$-calculus and a scalar kernel. The proof relies on the dilation theorem for positive definite operator families on a Hilbert space.
Consider the supremal functional \[ \tag{1} \label{1} E_\infty(u,A) \,:=\, \|L(\cdot,u,D u)\|_{L^\infty(A)},\quad A\subseteq Ω, \] applied to $W^{1,\infty}$ maps $u:Ω\subseteq \mathbb{R}\longrightarrow \mathbb{R}^N$, $N\geq 1$. Under certain assumptions on $L$, we prove for any given boundary data the existence of a map which is: i) a vectorial Absolute Minimiser of \eqref{1} in the sense of Aronsson, ii) a generalised solution to the ODE system associated to \eqref{1} as the analogue of the Euler-Lagrange equations, iii) a limit of minimisers of the respective $L^p$ functionals as $p\rightarr…
We construct the Schwartz kernel of resolvent and spectral measure for Schrödinger operators on the flat Euclidean cone $(X,g)$, where $X=C(\mathbb{S}_σ^1)=(0,\infty)\times \mathbb{S}_σ^1$ is a product cone over the circle, $\mathbb{S}_σ^1=\R/2πσ\Z$, with radius $σ>0$ and the metric $g=dr^2+r^2 dθ^2$. As products, we prove the dispersive estimates for the Schrödinger and half-wave propagators in this setting.
We give a uniform description of resolvents and complex powers of elliptic semiclassical cone differential operators as the semiclassical parameter $h$ tends to $0$. An example of such an operator is the shifted semiclassical Laplacian $h^2Δ_g+1$ on a manifold $(X, g)$ of dimension $n\geq 3$ with conic singularities. Our approach is constructive and based on techniques from geometric microlocal analysis: we construct the Schwartz kernels of resolvents and complex powers as conormal distributions on a suitable resolution of the space $[0,1)_h\times X\times X$ of $h$-dependent integral kernels; …
A symbolic calculus for a pseudo-differential operators acting on sections of a homogeneous vector bundle over a compact homogeneous space $G/H$ with compact $G$ and $H$ is developed. We realize the symbol of a pseudo-differential operator as a linear operator acting on corresponding irreducible unitary representations of $H$ valued in the algebra $C^\infty(G)$ of smooth functions. We write down how left invariant vector fields of $SU(2)$ act on the sections of homogeneous vector bundles associated to the fibration $\mathbb{T}\hookrightarrow SU(2)\rightarrow\mathbb{C}P^1$, which is known as th…
Complete Integrability for Hamiltonian Systems with a Cone Potential
已知如果$R^n$中的一点被一个有界的下势$V$所驱动,且该势的梯度总是在一个不含直线的闭凸锥中,那么当时间到达$+\infty$时,速度有一个有限的极限.作为初始数据的函数,渐近速度的分量是平凡的运动常数。我们找到了这些功能是$C^k$($2\le k \le+\infty$)的第一积分,独立和成对的对合的充分条件。这样我们就构造了一大类完全可积系统。我们可以处理非常不同的渐近行为的潜力,我们有持久性的可积性下的任何小扰动的潜力在任意紧集。
In this paper we utilise new methods of Calculus of Variations in $L^\infty$ to provide a regularisation strategy to the ill-posed inverse problem of identifying the source of a non-homogeneous linear elliptic equation, satisfying Dirichlet data on a domain. One of the advantages over the classical Tykhonov regularisation in $L^2$ is that the approximated solution of the PDE is uniformly close to the noisy measurements taken on a compact subset of the domain.
We introduce some families of generalized Black--Scholes equations which involve the Riemann-Liouville and Weyl space-fractional derivatives. We prove that these generalized Black--Scholes equations are well-posed in $(L^1-L^\infty)$-interpolation spaces. More precisely, we show that the elliptic type operators involved in these equations generate holomorphic semigroups. Then, we give explicit integral expressions for the associated solutions. In the way to obtain well-posedness, we prove a new connection between bisectorial operators and sectorial operators in an abstract setting. Such a conn…