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168,742 papers · 148 categories

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118237355473 · Jun 202019922001200920172026
48 results for Alexandrov estimate

In the previous work [35], the second and third authors established a Bochner type formula on Alexandrov spaces. The purpose of this paper is to give some applications of the Bochner type formula. Firstly, we extend the sharp lower bound estimates of spectral gap, due to Chen-Wang [9, 10] and Bakry-Qian [6], from smoot…

2011-02-21abs ↗pdf ↗

Estimates for polynomial operators using determinant majorization and subharmonics.

problem Bounding solutions of polynomial operators on Euclidean domains.
method Combines Alexandrov estimate and determinant majorization, using subharmonics and semiconvex approximation.
result Includes classical Alexandrov-Bakelman-Pucci estimate for linear operators.

New proof of Kähler-Einstein Fano manifold LL^\infty estimates.

problem Uniform LL^\infty estimates for Kähler-Ricci flow on Kähler-Einstein Fano manifolds.
method Using Chen-Cheng's auxiliary Monge-Ampère equation and the Alexandrov-Bakelman-Pucci maximum principle, without pluripotential theory.
result Uniform LL^\infty estimates derived for Kähler-Ricci flow on Kähler-Einstein Fano manifolds.

The paper measures and limits the extent of non-smooth points in Alexandrov spaces.

problem Understanding the extent of non-smooth points in Alexandrov spaces.
method Defining a non-negative function K(x)\mathcal K(x) to measure the extent of non-smoothness and quantitatively estimating its distribution.
result The Hausdorff dimension estimate and quantitative Hausdorff measure estimate for the set of C2C^2-singular points.

Paper doubles Hessian estimates for special Lagrangian equation with constraints.

problem Estimating Hessian for special Lagrangian equation under general phase constraints.
method Doubling argument, Alexandrov-type theorems.
result Established Hessian estimates for special Lagrangian equation.

Sharp upper bounds derived for Alexandrov-Fenchel deficit using weighted Minkowski integral formulas.

problem Deriving upper bounds for the Alexandrov-Fenchel deficit.
method Using weighted Minkowski integral formulas and an integral formula for the deficit in Jensen's inequality.
result Quantitative estimates under weaker convexity assumptions, including a distance term.

In this note, we study the radius of positively curved or non-negatively curved Alexandrov space with strictly convex boundary, with convexity measured by the Base-Angle defined by Alexander and Bishop. We also estimate the volume of the boundary of non-negatively curved spaces as well as the rigidity case, which can b…

2018-12-06abs ↗pdf ↗

For a path in a compact finite dimensional Alexandrov space XX with curv κ\ge κ, the two basic geometric invariants are the length and the turning angle (which measures the closeness from being a geodesic). We show that the sum of the two invariants of any loop is bounded from below in terms of κκ, the dimension, di…

2010-08-16abs ↗pdf ↗

This is the first paper of two ones. Here we prove that two compact Alexandrov surfaces of bounded integral curvature having no peak points are bi-Lipschitz equivalent if they are homeomorphic one to the other. Also conditions under that two ends having finite integral negative curvature are bi-Lipschitz equivalent are…

2004-09-20abs ↗pdf ↗

Sharp stability of Alexandrov's theorem for C1C^1 domains in the small-excess regime

problem Stability of Alexandrov's theorem for C1C^1 domains in the small-excess regime
method Combines a BVBV version of Fuglede's spectral-gap argument, a star-shaped rearrangement for sets of finite perimeter, quantitative estimates for the part of the boundary contained in the tentacles, and a polyhedral approximation argument for the non-graphical region
result Sharp stability estimate in a genuinely non-parametric regime

Our goal is to show the beauty and power of Alexandrov geometry by reaching interesting applications and theorems with a minimum of preparation. The topics include 1. Reshetnyak's gluing theorem, 2. Estimates on the number of collisions in billiards, 3. Reshetnyak's majorization theorem, 4. Hadamard--Cartan globalizati…

2017-01-12abs ↗pdf ↗

We study three-dimensional Alexandrov spaces with a lower curvature bound, focusing on extending three classical results on three-dimensional manifolds: First, we show that a closed three-dimensional Alexandrov space of positive curvature, with at least one topological singularity, must be homeomorphic to the suspensio…

2013-07-15abs ↗pdf ↗

The paper estimates singular sets in Alexandrov spaces and proves packing and Hausdorff measure estimates.

problem Estimating singular sets in Alexandrov spaces with curvature bounded below.
method Analyzing rr-scale (k,ε)(k,ε)-singular sets and using packing estimates to derive Hausdorff measure bounds.
result Hausdorff measure estimates for singular sets in Alexandrov spaces.

We obtain a structure theorem for closed, cohomogeneity one Alexandrov spaces and we classify closed, cohomogeneity one Alexandrov spaces in dimensions 3 and 4. As a corollary, we obtain the classification of closed, nn-dimensional, cohomogeneity one Alexandrov spaces admitting an isometric Tn1T^{n-1} action. In contra…

2009-10-27abs ↗pdf ↗

Developing a non-symmetric strainer theory for spaces with non-negative curvature beyond Alexandrov geometry.

problem Studying spaces with non-Riemannian curvature beyond Alexandrov geometry.
method Introducing a weak quadruple comparison principle and developing a strainer theory.
result Spaces have constant integer dimension, measure contraction property, and unique Banach tangent cones.

The paper improves stability estimates for soap bubble theorem in curved domains.

problem Stability estimates for the Soap Bubble Theorem in curved domains.
method Leveraging Gagliardo-Nirenberg-type interpolation inequalities.
result Optimal stability estimates for LrL^r deviations of mean curvature from being constant.

We prove a Lipschitz-Volume rigidity theorem in Alexandrov geometry, that is, if a 1-Lipschitz map f ⁣:X=⨿XYf\colon X=\amalg X_\ell\to Y between Alexandrov spaces preserves volume, then it is a path isometry and an isometry when restricted to the interior of XX. We furthermore characterize the metric structure on YY with re…

2011-10-25abs ↗pdf ↗

This paper introduces Alexandrov's theory of singular surfaces and their curvature.

problem Understanding the geometry of singular surfaces with intrinsic metrics and curvature.
method Develops the theory of Alexandrov surfaces, focusing on their convergence and stability properties.
result Classifies compact Alexandrov surfaces using the conformal viewpoint introduced by Reshetnyak.