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Xiaoshang Jin

Publications and source records attributed to Xiaoshang Jin.

At least 19 recordsLinked to original sources

Conformal Ricci Curvature and Spectral Estimates

We derive optimized upper bounds for the first Dirichlet eigenvalue of a bounded domain under lower bounds for the conformal Ricci tensor of Shen and Ye. The method also yields sharp estimates for the bottom spectrum on complete noncompact manifolds, a four-dimensional application involving $Q$-curvature, and local and global spectral-Ricci extensions of Cheng's estimate. As a consequence, we obtain a sharp comparison between the spectra of the Laplacian and the conformal Laplacian in terms of the smallest Schouten eigenvalue.

math.DG

Sharp $p$-Capacity Estimates via Quermassintegrals in Hyperbolic Space

This paper establishes sharp upper bounds for $p$-capacities $\mathrm{Cap}_{1 2m+1$, an interpolating radius combines the $2m$-th curvature-excess radius with the $L^\infty$ curvature scale, thereby linking the finite-moment and supremum regimes. Equality in the sharp comparisons characterizes geodesic balls.

math.DG

A Unified Quermassintegral Approach to Quasilinear Heat Dispersion and Loss

This paper establishes a fundamental connection between quasilinear potential theory and convex geometric analysis by investigating the interplay between the quasilinear Laplace operator and quermassintegrals. We introduce a quasilinear heat dispersion law for convex conductors and prove that, among all convex conductors of a fixed mean width, the closed ball is a unique maximizer of this dispersion. By characterizing the quasilinear heat loss of a convex conductor explicitly in terms of its quermassintegrals, we demonstrate not only a formal equivalence between the isocapacitary and isoperimetric inequalities in the setting of mathematical physics but also that, among all convex conductors of a fixed mean width, the closed ball is a unique maximizer of this loss. These results provide a novel bridge between the metric properties of convex conductors and the variational analysis of quasilinear elliptic operators, offering a unified perspective on sharp geometric inequalities and their extremal cases.

math.AP

Large $p$-Capacitary Invariants, Entropy, and Geometric Rank

We introduce large-$p$ asymptotic invariants associated with the $p$-capacity, the first $p$-eigenvalue, and the Maz'ya constant on connected complete noncompact Riemannian manifolds. For the two standard normalizations \[ p\,\operatorname{Cap}_p(Ω)^{1/p} \quad\text{and}\quad (p-1)\operatorname{Cap}_p(Ω)^{1/(p-1)}, \] we prove that their upper and lower limits are independent of the bounded smooth conductor $Ω$. We denote the conductor-independent upper limit of the first normalization by $\mathcal C(M)$. When the second normalization converges to a positive limit, its logarithmic second-order coefficient is also conductor-independent. These invariants satisfy \[ \mathcal V(M)\geq \mathcal C(M)\geq Λ(M)=\mathcal M(M)\geq0. \] Under centered-ball isoperimetry or rotational symmetry, together with an eventual monotonicity assumption on the sphere-area-to-ball-volume ratio, all four invariants coincide with the volume entropy. This yields hyperbolic rigidity from either maximal $p$-spectral data or maximal $\mathcal C(M)$, as well as an almost-rigidity theorem under Ricci curvature and diameter bounds. For the universal cover of a closed negatively curved manifold, both capacitary normalizations converge to the volume entropy, which equals the topological entropy of the geodesic flow, without any centered-ball isoperimetric or rotational-symmetry assumption. For nonflat Hadamard manifolds with compact quotient satisfying either of the above geometric conditions, we obtain a second-order large-$p$ expansion whose logarithmic coefficient detects the geometric rank. Finally, sharp examples show that the general inequalities may be strict and that the first-order capacitary limit need not exist.

math.DG

Estimates of $p$-capacity for manifolds with Ricci curvature bounded from below

We study sharp estimates for the $p$-capacity on complete non-compact Riemannian manifolds under lower Ricci curvature bounds. First, we establish sharp comparison inequalities for the $p$-capacity of bounded smooth domains in manifolds satisfying $\operatorname{Ric}\ge -ng.$ The estimates are expressed in terms of the boundary mean curvature and correspond to natural warped-product model ends. We characterize all equality cases and show that equality forces the exterior region to be isometric to the corresponding warped product. We also obtain an analogous sharp estimate under nonnegative Ricci curvature, whose equality case is described by an asymptotically flat model end. Second, we investigate normalized lower bounds for the relative $p$-capacity of condensers. We introduce scale-invariant quantities involving the volume of the inner set and the diameter of the ambient domain, establish uniform positive lower bounds, and determine the optimal ranges of the normalization parameters.

math.DG

Principal $p-$frequency estimates on non-compact manifolds with negative Ricci curvature

We establish a lower bound for the principal $p-$frequency $λ_{1,p}(Ω)$ on a bounded domain $Ω$ in a non-compact Riemannian manifold of dimension $n.$ Under the assumption that the Ricci curvature satisfies $\operatorname{Ric} \geq (n-1)K$ with $K<0,$ we prove that $λ_{1,p}(Ω) > \barλ_{D,K,n}$, where $D$ is the diameter of $Ω$ and $\barλ_{D,K,n}$ is explicitly defined as the first eigenvalue of an associated one-dimensional ordinary differential equation model that incorporates both $D$ and $K.$ Moreover, the estimate is sharp. This work extends previous results for the case $K=0$ to the geometrically more complex setting of negative Ricci curvature, and providing a new quantitative connection between the eigenvalue, the diameter of domains, and the curvature lower bound.

math.DG

Heat dispersion laws in smooth compact manifolds

Given a Lipschitz conductor $K$ in the smooth compact Riemannian $2\le n$-manifold $(M,g)$, such a half generic heat dispersion law $$ {\rm H^d}_{p,\varPhi,\varPsi}(K,M)=2^{-1} {\rm H^d}_{Δ_p,\varPhi,\varPsi}(K,M) $$ is not only newly-established via Theorem 1.1 but also deeply-explored through not only Proposition 3.1 (a comparison law for the generic heat dispersion) but also Proposition 3.2 (a recycling law for the quasilinear Laplace-Robin eigenvalue).

math.DG

On compactness conformally compact Einstein manifolds and uniqueness of Graham-Lee metrics, III

In this paper, we establish a compactness result for a class of conformally compact Einstein metrics defined on manifolds of dimension $d\ge 4$. As an application, we derive the global uniqueness of a class of conformally compact Einstein metric defined on the $d$-dimensional ball constructed in the earlier work of Graham-Lee with $d\ge 4$. As a second application, we establish some gap phenomenon for a class of conformal invariants.

math.DG

Lower bound for the first eigenvalue of $p-$Laplacian and applications in asymptotically hyperbolic Einstein manifolds

This paper investigates the first Dirichlet eigenvalue for the $p$-Laplacian in Riemannian manifolds. Firstly, we establish a lower bound for this eigenvalue under the condition that the domain includes a specific function which fulfills certain criteria related to divergence and gradient conditions. In the subsequent section, we introduce an enhanced lower bound for the eigenvalue, which is linked to the distance function defined in the domain. As a practical application, we provide an estimation for the first Dirichlet eigenvalue of geodesic balls with large radius in asymptotically hyperbolic Einstein manifolds.

math.DG

Essential $p$-capacity-volume estimates for rotationally symmetric manifolds

Given $p\in [1,\infty]$, this article presents the novel basic volumetric estimates for the relative $p$-capacities with their applications to finding not only the sharp weak $(p,q)$-imbeddings but also the precise lower bounds of the principal $p$-frequencies, which principally live in the rotationally symmetric manifolds.

math.DG

Willmore-type inequality for closed hypersurfaces in complete manifolds with Ricci curvature bounded below

In this paper, we establish a Willmore-type inequality for closed hypersurfaces in a complete Riemannian manifold of dimension $n+1$ with ${\rm Ric}\geq-ng$. It extends the classic result of Argostianiani, Fogagnolo, and Mazzieri in [1] to the Riemannian manifold of negative curvature. As an application, we construct a Willmore-type inequality for closed hypersurfaces in hyperbolic space and obtain the characterization of geodesic sphere.

math.DG

The relative volume function and the capacity of sphere on asymptotically hyperbolic manifolds

Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the egularity of this function. We use this function to give an accurate characterization of the height of the geodesic defining function for the AH manifold with a given boundary metric. It is also proved that such functions are uniformly bounded from below at infinity and the bound only depends on the dimension. As an application, we use this function to research the capacity of balls in AH manifold and provide some limit results.

math.DG

Asymptotic behavior of the first Dirichlet eigenvalue of AHE manifolds

In this article, we investigate the rate at which the first Dirichlet eigenvalue of geodesic balls decreases as the radius approaches infinity. We prove that if the conformal infinity of an asymptotically hyperbolic Einstein manifold is of nonnegative Yamabe type, then the two-term asymptotic of the eigenvalues is the same as that in hyperbolic space.

math.DG

Rigidity for inscribed radius estimate of asymptotically hyperbolic Einstein manifold

The inscribed radius of a compact manifold with boundary is bounded above if its Ricci curvature and mean curvature are bounded from below. The rigidity result implies that the upper bound can be achieved only in space form. In this paper, we generalize this result to asymptotically hyperbolic Einstein manifold. We get an upper bound of the relative volume of AH manifold and if we combine it with the recent work of Wang and Zhou, then the rigidity is obtained.

math.DG

Boundary Estimate of Asymptotically Hyperbolic Einstein Manifolds of Even Dimension

In this paper, we study the finite boundary regularity and estimates of an asymptotically hyperbolic Einstein manifold in even dimension $n+1.$ We show that if the initial compactification is $C^{n-1}$ and the $(n-3)$-th derivative of its scalar curvature is Hölder continuous, then the AHE metric is $C^{m,α}$ conformally compact provided the boundary metric is $C^{m,α}$. This is an improvement of Helliwell's result. We also provide an estimate of the Yamabe compactification metric in the new structure.

math.DG