Sharp Sobolev Inequalities for Vector Valued Maps

Sobolev and Hardy-Littlewood-Sobolev inequalities

This paper is devoted to improvements of Sobolev and Onofri inequalities. The additional terms involve the dual counterparts, i.e. Hardy-Littlewood-Sobolev type inequalities. The Onofri inequality is achieved as a limit case of Sobolev type inequalities. Then we focus our attention on the constants in our improved Sobolev inequalities, that can be estimated by completion of the square methods. Our estimates rely on nonlinear flows and spectral problems based on a linearization around optimal Aubin-Talenti functions.

The Frank-Lieb approach to sharp Sobolev inequalities

Frank and Lieb gave a new, rearrangement-free, proof of the sharp Hardy-Littlewood-Sobolev inequalities by exploiting their conformal covariance. Using this they gave new proofs of sharp Sobolev inequalities for the embeddings $W^{k,2}(\mathbb{R}^n)\hookrightarrow L^{\frac{2n}{n-2k}}(\mathbb{R}^n)$. We show that their argument gives a direct proof of the latter inequalities without passing through Hardy-Littlewood-Sobolev inequalities, and, moreover, a new proof of a sharp fully nonlinear Sobolev inequality involving the $σ_2$-curvature. Our argument relies on nice commutator identities deduce…

A derivation of the sharp Moser-Trudinger-Onofri inequalities from the fractional Sobolev inequalities

We derive the sharp Moser-Trudinger-Onofri inequalities on the standard $n$-sphere and CR $(2n+1)$- sphere as the limit of the sharp fractional Sobolev inequalities for all $n\ge 1$. On the $2$-sphere and $4$-sphere, this was established recently by S.-Y. Chang and F. Wang. Our proof uses an alternative and elementary argument.

球面上反向Sobolev不等式及单位球上Sobolev迹不等式的一个简单证明

A simple proof of reverse Sobolev inequalities on the sphere and Sobolev trace inequalities on the unit ball

本文给出球面上反向Sobolev不等式及单位球上Sobolev迹不等式的简单证明，利用反向HLS不等式和质心条件，并建立定量稳定性。

Composition operators on Sobolev spaces, $Q$-mappings and weighted Sobolev inequalities

In this paper we give connections between mappings which generate bounded composition operators on Sobolev spaces and $Q$-mappings. On this base we obtain measure distortion properties $Q$-homeomorphisms. Using the composition operators on Sobolev spaces we obtain weighted Sobolev inequalities with special weights which are Jacobians of $Q$-mappings.

Composition operators on Sobolev spaces and weighted moduli inequalities

In this paper we study connections between composition operators on Sobolev spaces and mappings defined by $p$-moduli inequalities ($p$-capacity inequalities). We prove that weighted moduli inequalities lead to composition operators on corresponding Sobolev spaces and inverse, composition operators on Sobolev spaces imply weighted moduli inequalities.

Logarithmic Sobolev inequalities for Dunkl operators with applications to functional inequalities for singular Boltzmann-Gibbs measures

In this paper we study several inequalities of log-Sobolev type for Dunkl operators. After proving an equivalent of the classical inequality for the usual Dunkl measure $μ_k$, we also study a number of inequalities for probability measures of Boltzmann type of the form $e^{-|x|^p} dμ_k$. These are obtained using the method of $U$-bounds. Poincaré inequalities are obtained as consequences of the log-Sobolev inequality. The connection between Poincaré and log-Sobolev inequalities is further examined, obtaining in particular tight log-Sobolev inequalities. Finally, we study application to exponen…

Interpolation inequalities between Sobolev and Morrey-Campanato spaces: A common gateway to concentration-compactness and Gagliardo-Nirenberg interpolation inequalities

We prove interpolation estimates between Morrey-Campanato spaces and Sobolev spaces. These estimates give in particular concentration-compactness inequalities in the translation-invariant and in the translation- and dilation-invariant case. They also give in particular interpolation estimates between Sobolev spaces and functions of bounded mean oscillation. The proofs rely on Sobolev integral representation formulae and maximal function theory. Fractional Sobolev spaces are also covered.

A note on higher order fractional Hardy-Sobolev inequalities

We establish some qualitative properties of minimizers in the fractional Hardy--Sobolev inequalities of arbitrary order.

紧致黎曼流形上Sobolev不等式的定量稳定性

Quantitative stability of Sobolev inequalities on compact Riemannian manifolds

本文研究紧致黎曼流形上Sobolev不等式的定量稳定性，证明近临界函数在$W^{1,2}$意义下接近极值函数集合，并涵盖次临界情形及退化现象。

Hardy-Sobolev inequalities with distance to the boundary weight functions

This is the first part of our research on certain sharp Hardy-Sobolev inequalities and the related elliptic equations. In this part we shall establish some sharp weighted Hardy-Sobolev inequalities whose weights are distance functions to the boundary.

Conductor inequalities and criteria for Sobolev-Lorentz two-weight inequalities

In this paper we present integral conductor inequalities connecting the Lorentz p,q-(quasi)norm of a gradient of a function to a one-dimensional integral of the p,q-capacitance of the conductor between two level surfaces of the same function. These inequalities generalize an inequality obtained by the second author in the case of the Sobolev norm. Such conductor inequalities lead to necessary and sufficient conditions for Sobolev-Lorentz type inequalities involving two arbitrary measures.

Reverse Stein-Weiss, Hardy-Littlewood-Sobolev, Hardy, Sobolev and Caffarelli-Kohn-Nirenberg inequalities on homogeneous groups

In this note we prove the reverse Stein-Weiss inequality on general homogeneous Lie groups. The obtained results extend previously known inequalities. Special properties of homogeneous norms and the reverse integral Hardy inequality play key roles in our proofs. Also, we show reverse Hardy, Hardy-Littlewood-Sobolev, Lp-Sobolev and Lp-Caffarelli-Kohn-Nirenberg inequalities on homogeneous groups.

Hardy inequalities in fractional Orlicz-Sobolev spaces

In this article we prove both norm and modular Hardy inequalities for a class functions in one-dimensional fractional Orlicz-Sobolev spaces.

Sobolev and Hardy-Littlewood-Sobolev inequalities: duality and fast diffusion

In the euclidean space, Sobolev and Hardy-Littlewood-Sobolev inequalities can be related by duality. In this paper, we investigate how to relate these inequalities using the flow of a fast diffusion equation in dimension $d\ge3$. The main consequence is an improvement of Sobolev's inequality when $d\ge5$, which involves the various terms of the dual Hardy-Littlewood-Sobolev inequality. In dimension $d=2$, Onofri's inequality plays the role of Sobolev's inequality and can also be related to its dual inequality, the logarithmic Hardy-Littlewood-Sobolev inequality, by a super-fast diffusion equat…

Maximizers for the Strichartz inequalities and the Sobolev-Strichartz inequalities for the Schrödinger equation

In this paper, we first show that there exists a maximizer for the non-endpoint Strichartz inequalities for the Schrödinger equation in all dimensions based on the recent linear profile decomposition results. We then present a new proof of the linear profile decomposition for the Schröindger equation with initial data in the homogeneous Sobolev space; as a consequence, there exists a maximizer for the Sobolev-Strichartz inequality.

Fractional Hardy-Sobolev inequalities on half spaces

We investigate the existence of extremals for Hardy-Sobolev inequalities involving the Dirichlet fractional Laplacian of order s, 0<s<1, on half-spaces.

Limit of Fractional Power Sobolev Inequalities

We derive the Moser-Trudinger-Onofri inequalities on the 2-sphere and the 4-sphere as the limiting cases of the fractional power Sobolev inequalities on the same spaces, and justify our approach as the dimensional continuation argument initiated by Thomas P. Branson.

分数Sobolev对数不等式

Fractional Sobolev logarithmic inequalities

本文提出了一种分数Sobolev对数不等式，通过插值不等式和变分问题，扩展了经典Sobolev不等式到非局部框架，并提供了新的分析工具。

关于区域分数阶 Sobolev 不等式中的尖锐常数

On the sharp constants in the regional fractional Sobolev inequalities

该工作聚焦区域分数阶 Laplace 算子对应的分数阶 Sobolev 不等式，核心问题是刻画其中的尖锐常数。

Sharp Sobolev inequalities involving boundary terms revisited

We revisit the sharp Sobolev inequalities involving boundary terms on Riemannian manifolds with boundaries proved by \emph{[Y.Y. Li and M. Zhu, Geom. Funct. Anal. \textbf{8} (1998), 59--87.]} and explore the role of the mean curvature.

Extremal problem of Hardy-Littlewood-Sobolev inequalities on compact Riemannian manifolds

This paper studies the existence of extremal problems for the Hardy-Littlewood-Sobolev inequalities on compact manifolds without boundary via Concentration-Compactness principle.

Symmetrization and sharp Sobolev inequalities in metric spaces

We derive sharp Sobolev inequalities for Sobolev spaces on metric spaces. In particular, we obtain new sharp Sobolev embeddings and Faber-Krahn estimates for Hörmander vector fields.

Fractional Sobolev inequalities associated with singular problems

In this paper we consider Sobolev inequalities associated with singular problems for the fractional $p$-Laplacian operator in a bounded domain of $\mathbb{R}^{N}$, $N\geq 2$.

Mosco convergence of Sobolev spaces and Sobolev inequalities for nonsmooth domains

We find extremely general classes of nonsmooth open sets which guarantee Mosco convergence for corresponding Sobolev spaces and the validity of Sobolev inequalities with a uniform constant. An important feature of our results is that the conditions we impose on the open sets for Mosco convergence and for the Sobolev inequalities are of the same nature, therefore it is easy to check when both are satisfied. Our analysis is motivated, in particular, by the study of the stability of the direct acoustic scattering problem with respect to the scatterer, which we also discuss. Concerning Mosco conve…

Sobolev mappings and moduli inequalities on Carnot groups

In the article we study mappings of Carnot groups satisfy moduli inequalities. We prove that homeomorphisms satisfy the moduli inequalities ($Q$-homeomor\-phisms) with a locally integrable function $Q$ are Sobolev mappings. On this base in the frameworks of the weak inverse mapping theorem we prove that mappings inverse to Sobolev homeomorphisms of finite distortion of the class $W^1_{ν,\text{loc}}(Ω;Ω')$ belong to the Sobolev class $W^1_{1,\text{loc}}(Ω';Ω)$.

Adimensional weighted Sobolev inequalities in PI spaces

We provide a family of global weighted Sobolev inequalities and Hardy inequalities on PI spaces with possibly non-maximal volume growth. Our results apply notably to non-trivial Ahlfors regular spaces like Laakso spaces and Kleiner-Schioppa spaces.

具有显式下界的Hardy-Littlewood-Sobolev不等式的稳定性

Stability of Hardy-Littlewood-Sobolev inequalities with explicit lower bounds

本文建立了具有显式下界的Hardy-Littlewood-Sobolev不等式及其分数阶Sobolev不等式的稳定性，推广了已有结果，证明基于竞争对称性和对偶稳定性理论。

Corrigenda to "$L^p$ estimates and asymptotic behavior for finite energy solutions of extremals to Hardy-Sobolev inequalities", Trans. Amer. Math. Soc. 363 (2011), no. 1, 37--62

Corrigenda to "$L^p$ estimates and asymptotic behavior for finite energy solutions of extremals to Hardy-Sobolev inequalities", Trans. Amer. Math. Soc. 363 (2011), no. 1, 37--62.

Existence of maximizers for Sobolev-Strichartz inequalities

We prove the existence of maximizers of Sobolev-Strichartz estimates for a general class of propagators, involving relevant examples, as for instance the wave, Dirac and the hyperbolic Schrodinger flows.

对数加权Sobolev空间中改进的Hardy型不等式

On improved Hardy-type inequalities in Log-Weighted Sobolev Spaces

本文在对数加权Sobolev空间中证明尖锐Hardy型不等式，并通过添加最优余项实现无穷级数改进，进而得到最优Leray-Trudinger型改进及两类不等式间的插值。

Sharp Logarithmic Sobolev and related inequalities with monomial weights

We derive a sharp Logarithmic Sobolev inequality with monomial weights starting from a sharp Sobolev inequality with monomial weights. Several related inequalities such as Shannon type and Heisenberg's uncertain type are also derived. A characterization of the equality case for the Logarithmic Sobolev inequality is given when the exponents of the monomial weights are all zero or integers. Such a proof is new even in the unweighted case.

径向函数在分数库仑-索博列夫空间中的加利亚尔多-尼伦伯格不等式

Gagliardo-Nirenberg Inequalities in Fractional Coulomb-Sobolev spaces for Radial functions

本文针对径向函数在分数库仑-索博列夫空间中扩展了加利亚尔多-尼伦伯格插值不等式的参数范围，并进一步分析了该扩展范围的最优性。

带边界项的加权Hardy-Sobolev型不等式

Weighted Hardy-Sobolev type inequalities with boundary terms

本文提出带边界项的加权Hardy-Sobolev型不等式，推导出相应的加权Sobolev和迹型不等式，用于分析无界域中椭圆问题的边界条件。

Hardy-Littlewood-Sobolev Inequalities via Fast Diffusion Flows

We give a simple proof of the $λ= d-2$ cases of the sharp Hardy-Littlewood-Sobolev inequality for $d\geq 3$, and the sharp Logarithmic Hardy-Littlewood-Sobolev inequality for $d=2$ via a monotone flow governed by the fast diffusion equation.

Pointwise Symmetrization Inequalities for Sobolev functions and applications

We develop a technique to obtain new symmetrization inequalities that provide a unified framework to study Sobolev inequalities, concentration inequalities and sharp integrability of solutions of elliptic equations

Singular subelliptic equations and Sobolev inequalities on nilpotent Lie groups

In this article we study singular subelliptic $p$-Laplace equations and best constants in Sobolev inequalities on nilpotent Lie groups. We prove solvability of these subelliptic $p$-Laplace equations and existence of the minimizer of the corresponding variational problem. It leads to existence of the best constant in the corresponding $(q,p)$-Sobolev inequality, $0<q<1$, $1<p<ν$.

A mass transportation approach for Sobolev inequalities in variable exponent spaces

In this paper we provide a proof of the Sobolev-Poincaré inequality for variable exponent spaces by means of mass transportation methods. The importance of this approach is that the method is exible enough to deal with different inequalities. As an application, we also deduce the Sobolev-trace inequality improving the result obtained by Fan.

Several Weighted Hardy, Hardy-Sobolev-Maz'ya and Related Inequalities

In this paper we establish several Hardy and Hardy-Sobolev type inequalities with homogeneous weights on the first orthant $\displaystyle \mathbb{R}_{*}^n:=\{(x_1, \ldots, x_n):x_1>0, \ldots, x_n>0 \}$. We then use some of them to produce Hardy type inequalities with remainder terms. Furthermore, we obtain some interpolation inequalities and Maz'ya type inequalities with remainder terms with the help of Maz'ya inequality and Sobolev inequality of Cabré and Ros-Orton on the upper half space $\mathbb{R}_{+}^n:=\{x=(x_1, \ldots, x_n)|\, x_n>0 \}$.

H型群上精确的分数阶Sobolev及相关不等式

Sharp fractional Sobolev and related inequalities on H-type groups

本文确定了H型群上与次拉普拉斯算子共形不变分数阶幂相关的分数阶Sobolev不等式的精确常数，并由此导出精确的log-Sobolev不等式与Sobolev迹不等式，推广了前人结果。

The existence of extremal functions for discrete Sobolev inequalities on lattice graphs

In this paper, we study the existence of extremal functions of the discrete Sobolev inequality and Hardy-Littlewood-Sobolev inequality on lattice graphs. We introduce the discrete Concentration-Compactness principle, and prove the existence of extremal functions for the best constants in the supercritical cases.

Parabolic weighted Sobolev-Poincaré type inequalities

We derive weighted Sobolev-Poincaré type inequalities in function spaces concerned with parabolic partial differential equations. We consider general weights depending on both space and time variables belonging to a Muckenhoupt class, so-called the parabolic $A_p$-class, where only the parabolic cubes are involved in the definition.

Hardy-Littlewood-Sobolev and Stein-Weiss inequalities on homogeneous Lie groups

In this note we prove the Stein-Weiss inequality on general homogeneous Lie groups. The obtained results extend previously known inequalities. Special properties of homogeneous norms play a key role in our proofs. Also, we give a simple proof of the Hardy-Littlewood-Sobolev inequality on general homogeneous Lie groups.

Characterizations of Sobolev inequalities on metric spaces

We present isocapacitary characterizations of Sobolev inequalities in very general metric measure spaces.

Non-local equations and optimal Sobolev inequalities on compact manifolds

This paper deals with fractional Sobolev spaces on a compact Riemannian manifold. We prove a Sobolev inequality in the critical range with an optimal constant for these fractional Sobolev spaces. We use this result to study the existence of a non-trivial solution for equations driven by a non-local integro-differential operator $\mathcal{L}_{\mathcal{K}}$ with critical non-linearity.

Reverse Hardy-Littlewood-Sobolev inequalities

This paper is devoted to a new family of reverse Hardy-Littlewood-Sobolev inequalities which involve a power law kernel with positive exponent. We investigate the range of the admissible parameters and characterize the optimal functions. A striking open question is the possibility of concentration which is analyzed and related with nonlinear diffusion equations involving mean field drifts.

Two limits on Hardy and Sobolev inequalities

It is known that classical Hardy and Sobolev inequalities hold when the exponent $p$ and the dimension $N$ satisfy $p < N < \infty$. In this note, we consider two limits of Hardy and Sobolev inequalities as $p \nearrow N$ and $N \nearrow \infty$ in some sense.

李群上的对数Sobolev型不等式

Logarithmic Sobolev-type inequalities on Lie groups

本文在一般李群、分级李群和分层群上建立并推广了多种对数Sobolev型不等式，包括Gross型、加权版本及Nash不等式，并应用于热方程衰减率估计。

Sharp Morrey-Sobolev inequalities on complete Riemannian Manifolds

Two Morrey-Sobolev inequalities (with support-bound and $L^1-$bound, respectively) are investigated on complete Riemannian manifolds with their sharp constants in $\mathbb R^n$. We prove the following results in both cases: $\bullet$ If $(M,g)$ is a {\it Cartan-Hadamard manifold} which verifies the $n-$dimensional Cartan-Hadamard conjecture, sharp Morrey-Sobolev inequalities hold on $(M,g)$. Moreover, extremals exist if and only if $(M,g)$ is isometric to the standard Euclidean space $(\mathbb R^n,e)$. $\bullet$ If $(M,g)$ has {\it non-negative Ricci curvature}, $(M,g)$ supports the sharp Morr…

Hardy-Littlewood-Sobolev and related inequalities: stability

The purpose of this text is twofold. We present a review of the existing stability results for Sobolev, Hardy-Littlewood-Sobolev (HLS) and related inequalities. We also contribute to the topic with some observations on constructive stability estimates for (HLS).

On a class of weighted anisotropic Sobolev inequalities

In this article, motivated by a work of Caffarelli and Cordoba in phase transitions analysis, we prove new weighted anisotropic Sobolev type inequalities, that is Sobolev type inequalities where different derivatives have different weight functions. The inequalities we are dealing with, are also intimately connected to weighted Sobolev inequalities for Grushin type operators, the weights being not necessarily Muckenhoupt. For example we consider here Sobolev inequalities on finite cylinders, the weights being different powers of the distance function from the top and the bottom of the cylinder…

Isoperimetry and symmetrization for logarithmic Sobolev inequalities

Using isoperimetry and symmetrization we provide a unified framework to study the classical and logarithmic Sobolev inequalities. In particular, we obtain new Gaussian symmetrization inequalities and connect them with logarithmic Sobolev inequalities. Our methods are very general and can be easily adapted to more general contexts.

Sharp Adams type inequalities in Sobolev spaces $W^{m,\frac{n}{m}}(\mathbb{R}^{n})$ for arbitrary integer $m$

The main purpose of our paper is to prove sharp Adams-type inequalities in unbounded domains of $\mathbb{R}^{n}$ for the Sobolev space $W^{m,\frac{n}{m}}\left(\mathbb{R} ^{n}\right)$ for any positive integer $m$ less than $n$. Our results complement those of Ruf and Sani \cite{RS} where such inequalities are only established for even integer $m$. Our inequalities are also a generalization of the Adams-type inequalities in the special case $n=2m=4$ proved in \cite{Y} and stronger than those in \cite{RS} when $n=2m$ for all positive integer $m$ by using different Sobolev norms.

Sobolev不等式在非线性Dirichlet形式中的应用

Sobolev inequalities for nonlinear Dirichlet forms

本文研究了非线性Dirichlet形式中Sobolev不等式与等容量不等式之间的等价关系。