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This paper investigates the identification of two coefficients in a coupled hyperbolic system with an observation on one component of the solution. Based on the the Carleman estimate for coupled wave equations a logarithmic type stability…

Analysis of PDEs · Mathematics 2020-11-19 Fangfang Dou , Masahiro Yamamoto

We prove a homotopy formula which yields almost sharp estimates in all (positive-indexed) Sobolev and H\"older-Zygmund spaces for the $\overline \partial$ equation on pseudoconvex domains of finite type in $\mathbb C^2$, extending the…

Complex Variables · Mathematics 2025-05-28 Ziming Shi

There is a family of potentials that minimize the lowest eigenvalue of a Schr\"odinger eigenvalue under the constraint of a given L^p norm of the potential. We give effective estimates for the amount by which the eigenvalue increases when…

Analysis of PDEs · Mathematics 2013-05-15 Eric A. Carlen , Rupert L. Frank , Elliott H. Lieb

For $\alpha >1$ we consider the initial value problem for the dispersive equation $i\partial_t u +(-\Delta)^{\alpha/2} u= 0$. We prove an endpoint $L^p$ inequality for the maximal function $\sup_{t\in[0,1]}|u(\cdot,t)|$ with initial values…

Classical Analysis and ODEs · Mathematics 2010-05-06 Keith M. Rogers , Andreas Seeger

We prove a Hardy inequality on convex sets, for fractional Sobolev-Slobodecki\u{\i} spaces of order $(s,p)$. The proof is based on the fact that in a convex set the distance from the boundary is a superharmonic function, in a suitable…

Analysis of PDEs · Mathematics 2018-06-12 Lorenzo Brasco , Eleonora Cinti

The aim of this note is to prove sharp regularity estimates for solutions of the continuity equation associated to vector fields of class $W^{1,p}$ with $p>1$. The regularity is of "logarithmic order" and is measured by means of suitable…

Analysis of PDEs · Mathematics 2022-02-09 Elia Bruè , Quoc-Hung Nguyen

We prove sharp stability estimates for the variation of the eigenvalues of non-negative self-adjoint elliptic operators of arbitrary even order upon variation of the open sets on which they are defined. These estimates are expressed in…

Spectral Theory · Mathematics 2012-10-15 Victor Burenkov , Pier Domenico Lamberti

In this short paper we prove a global logarithmic stability of the Cauchy problem for H 2-solutions of an anisotropic elliptic equation in a Lip-schitz domain. The result we obtained is based on tools borrowed from the existing technics to…

Analysis of PDEs · Mathematics 2019-03-05 Mourad Choulli

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…

Differential Geometry · Mathematics 2020-02-28 Jeffrey S. Case

We prove sharp inequalities of Hardy type for functions in the Sobolev space $W^{1,p}$ on the unit sphere $\mathbb{S}^{n-1}$ in $\mathbb{R}^{n}$. We achieve this in both the subcritical and critical cases. The method we use to show…

Functional Analysis · Mathematics 2020-06-15 Ahmed A. Abdelhakim

We establish a sharp affine $L^p$ Sobolev trace inequality by using the $L_p$ Busemann-Petty centroid inequality. For $p = 2$, our affine version is stronger than the famous sharp $L^2$ Sobolev trace inequality proved independently by…

Functional Analysis · Mathematics 2025-03-14 Pablo Luis De Nápoli , Julián Haddad , Carlos Hugo Jiménez , Marcos Montenegro

We show that on $\mathbb S^1(1/\sqrt{d-2})\times\mathbb S^{d-1}(1)$ the conformally invariant Sobolev inequality holds with a remainder term that is the fourth power of the distance to the optimizers. The fourth power is best possible. This…

Analysis of PDEs · Mathematics 2022-06-02 Rupert L. Frank

Let $W^1L^{p,q}(\mathbb H^n)$, $1\leq q,p < \infty$ denote the Lorentz-Sobolev spaces of order one in the hyperbolic spaces $\mathbb H^n$. Our aim in this paper is three-fold. First of all, we establish a sharp Poincar\'e inequality in…

Functional Analysis · Mathematics 2020-01-14 Van Hoang Nguyen

We consider Gagliardo-Nirenberg inequalities on the sphere which interpolate between the Poincar\'e inequality and the Sobolev inequality, and include the logarithmic Sobolev inequality as a special case. We establish explicit stability…

Analysis of PDEs · Mathematics 2024-01-24 Giovanni Brigati , Jean Dolbeault , Nikita Simonov

We show that for a hypoelliptic Dirichlet form operator A on a stratified complex Lie group, if the logarithmic Sobolev inequality holds, then a holomorphic projection of A is strongly hypercontractive in the sense of Janson. This extends…

Analysis of PDEs · Mathematics 2018-11-30 Nathaniel Eldredge , Leonard Gross , Laurent Saloff-Coste

In this paper, we continue the investigation on the connection between observability and inverse problems for a class of parabolic equations with unbounded first order coefficients. We prove new logarithmic stability estimates for a class…

Analysis of PDEs · Mathematics 2023-05-30 S. E. Chorfi , L. Maniar

In this paper, we study the problem of robust stabilization for linear time-varying (LTV) systems subject to time-varying normalized coprime factor uncertainty. Operator theoretic results which generalize similar results known to hold for…

Optimization and Control · Mathematics 2012-07-31 Seddik M. Djouadi

We prove quantitative stability of isometries on the first Heisenberg group with sub-Riemannian geometry: every $ (1+ \varepsilon)$-quasi-isometry of the John domain of the Heisenberg group $ \mathbb {H} $ is close to some isometry with…

Functional Analysis · Mathematics 2022-05-06 Daria Isangulova

This paper contains two main contributions. First, it provides optimal stability estimates for advection-diffusion equations in a setting in which the velocity field is Sobolev regular in the spatial variable. This estimate is formulated…

Analysis of PDEs · Mathematics 2021-08-24 Víctor Navarro-Fernández , André Schlichting , Christian Seis

We derive sufficient conditions for a probability measure on a finite product space (a spin system) to satisfy a (modified) logarithmic Sobolev inequality. We establish these conditions for various examples, such as the (vertex-weighted)…

Probability · Mathematics 2020-05-15 Holger Sambale , Arthur Sinulis