Results 71 to 80 of about 47,687 (176)
On curvature tensors of Norden and metallic pseudo-Riemannian manifolds
Complex Manifolds, 2019 We study some properties of curvature tensors of Norden and, more generally, metallic pseudo-Riemannian manifolds. We introduce the notion of J-sectional and J-bisectional curvature of a metallic pseudo-Riemannian manifold (M, J, g) and study their ...
Blaga Adara M., Nannicini Antonella
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Communications on Pure and Applied Mathematics, Volume 78, Issue 9, Page 1656-1702, September 2025.Abstract Let (Mn,g)$(M^n,g)$ be a complete Riemannian manifold which is not isometric to Rn$\mathbb {R}^n$, has nonnegative Ricci curvature, Euclidean volume growth, and quadratic Riemann curvature decay. We prove that there exists a set G⊂(0,∞)$\mathcal {G}\subset (0,\infty)$ with density 1 at infinity such that for every V∈G$V\in \mathcal {G}$ there ...
Gioacchino Antonelli +2 more
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Riemannian manifolds with positive radial curvature
Japanese journal of mathematics. New series, 1993 The authors prove the following results. Theorem A: A complete noncompact Riemannian manifold \(M\) of positive minimal radial curvature has exactly one end. Theorem B: If the minimal radial curvature of \(M\) is bounded below by 1 and if the volume of \(M\) is greater than 3/4 \(\omega_ n\), where \(\omega_ n\) is the volume of the unit \(n\)-sphere \(
Yoshiroh Machigashira +1 more
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Communications on Pure and Applied Mathematics, Volume 78, Issue 9, Page 1783-1842, September 2025.Abstract We consider the global dynamics of finite energy solutions to energy‐critical equivariant harmonic map heat flow (HMHF) and radial nonlinear heat equation (NLH). It is known that any finite energy equivariant solutions to (HMHF) decompose into finitely many harmonic maps (bubbles) separated by scales and a body map, as approaching to the ...
Kihyun Kim, Frank Merle
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Simply connected Alexandrov 4-manifolds with positive or nonnegative curvature and torus actions [PDF]
, 2013 We point out that a 4-dimensional topological manifold with an Alexandrov metric (of curvature bounded below) and with an effective, isometric action of the circle or the 2-torus is locally smooth.
Galaz-Garcia, Fernando
core
Global and microlocal aspects of Dirac operators: Propagators and Hadamard states
Mathematische Nachrichten, Volume 298, Issue 9, Page 2942-2974, September 2025.Abstract We propose a geometric approach to construct the Cauchy evolution operator for the Lorentzian Dirac operator on Cauchy‐compact globally hyperbolic 4‐manifolds. We realize the Cauchy evolution operator as the sum of two invariantly defined oscillatory integrals—the positive and negative Dirac propagators—global in space and in time, with ...
Matteo Capoferri, Simone Murro
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WIREs Computational Statistics, Volume 17, Issue 3, September 2025.The halfspace depth generalizes quantiles to multivariate data. This is a bagplot—a depth‐based analog of a boxplot. It succinctly captures the geometry of the bivariate dataset (blue/red points) and identifies the four red points in the top left corner as deviating from the general pattern of the data.
Stanislav Nagy
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Curvature flows in semi-Riemannian manifolds [PDF]
Surveys in Differential Geometry, 2007 We prove that the limit hypersurfaces of converging curvature flows are stable, if the initial velocity has a weak sign, and give a survey of the existence and regularity results.
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Statistical disaggregation—A Monte Carlo approach for imputation under constraints
Scandinavian Journal of Statistics, Volume 52, Issue 3, Page 1376-1421, September 2025.Abstract Equality‐constrained models naturally arise in problems in which the measurements are taken at different levels of resolution. The challenge in this setting is that the models usually induce a joint distribution which is intractable. Resorting to instead sampling from the joint distribution by means of a Monte Carlo approach is also ...
Shenggang Hu +5 more
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Deformations of Anosov subgroups: Limit cones and growth indicators
Journal of the London Mathematical Society, Volume 112, Issue 3, September 2025.Abstract Let G$G$ be a connected semisimple real algebraic group. We prove that limit cones vary continuously under deformations of Anosov subgroups of G$G$ under a certain convexity assumption, which turns out to be necessary. We apply this result to the notion of sharpness for the action of a discrete subgroup on a non‐Riemannian homogeneous space ...
Subhadip Dey, Hee Oh
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