Results 31 to 40 of about 39,694 (133)
Stochastic Gradient Descent in High Dimensions for Multi‐Spiked Tensor PCA
Communications on Pure and Applied Mathematics, Volume 79, Issue 10, Page 2291-2369, October 2026.ABSTRACT We study the high‐dimensional dynamics of online stochastic gradient descent (SGD) for the multi‐spiked tensor model. This multi‐index model arises from the tensor principal component analysis (PCA) problem with multiple spikes, where the goal is to estimate the unknown signal vectors within the N$N$‐dimensional unit sphere through maximum ...
Gérard Ben Arous +2 more
wiley +1 more source
Free semigroups of large critical exponent
Journal of Topology, Volume 19, Issue 3, September 2026.Abstract For a convergence group equipped with an expanding coarse‐cocycle, we construct finitely generated free subsemigroups, which we call Bishop−−Jonessemigroups$\textit{Bishop--Jones semigroups}$, of critical exponent arbitrarily close to but strictly less than the critical exponent of the ambient group.
Aleksander Skenderi
wiley +1 more source
Surface subgroups for cocompact lattices of isometries of H2n$\mathbb {H}^{2n}$
Journal of Topology, Volume 19, Issue 3, September 2026.Abstract We prove the existence of surface subgroups within any cocompact lattice Γ$\Gamma$ in SO(2n,1)$\mathrm{SO}(2n,1)$ for n⩾2$n\geqslant 2$. This result addresses the cases missing from the work of Hamenstädt in 2015, who constructed surface subgroups in cocompact lattices for all other rank‐1 simple Lie groups of noncompact type.
Jeremy Kahn, Zhenghao Rao
wiley +1 more source
Invariant Measure and Universality of the 2D Yang–Mills Langevin Dynamic
Communications on Pure and Applied Mathematics, Volume 79, Issue 8, Page 1973-2102, August 2026.ABSTRACT We prove that the Yang–Mills (YM) measure for the trivial principal bundle over the two‐dimensional torus, with any connected, compact structure group, is invariant for the associated renormalised Langevin dynamic. Our argument relies on a combination of regularity structures, lattice gauge‐fixing and Bourgain's method for invariant measures ...
Ilya Chevyrev, Hao Shen
wiley +1 more source
Kuga–Satake Construction on Families of K3 Surfaces of Picard Rank 14
Mathematische Nachrichten, Volume 299, Issue 8, Page 1894-1916, August 2026.ABSTRACT The isometry between the type IV6 and the type II4 hermitian symmetric domains suggests a possible relation between suitable moduli spaces of K3 surfaces of Picard rank 14 and of polarized abelian 8‐folds with totally definite quaternion multiplication. We show how this isometry induces a geometrically meaningful map between such moduli spaces
Flora Poon
wiley +1 more source
Efficient Tensor Completion Algorithms for Highly Oscillatory Operators
Numerical Linear Algebra with Applications, Volume 33, Issue 4, August 2026.ABSTRACT We address the problem of recovering highly oscillatory operators, represented as n×n$$ n\times n $$ matrices with a fixed set of observed entries. Given that these matrices can be well compressed by butterfly matrix decomposition of L=𝒪(logn) levels requiring only O(nlogn)$$ O\left(n\log n\right) $$ degrees of freedom, we propose a novel ...
Navjot Singh +3 more
wiley +1 more source
Fortschritte der Physik, Volume 74, Issue 8, August 2026.ABSTRACT We apply the boundary‐only isothermal formulation of finite‐distance weak gravitational deflection to regular black holes, black‐bounces, traversable wormholes, non‐asymptotically flat backgrounds, and static quadrupolar spacetimes. The methodological advance is not a new value for a known bending angle.
Reggie C. Pantig, Ali Övgün
wiley +1 more source
Intrinsic Shape LDA With Application to Body Human Shapes Classification
Statistical Analysis and Data Mining: An ASA Data Science Journal, Volume 19, Issue 4, August 2026.ABSTRACT Advancements in 3D scanning and cloud infrastructure enable the acquisition and analysis of high‐density body surface datasets. In this work, we propose a novel methodology that extends linear discriminant analysis (LDA) to Kendall's shape space for the classification of 3D objects, specifically human body shapes.
Jorge Valero +3 more
wiley +1 more source
Cloud‐Plots for Spherical Data With Applications to Glaucoma and Gait Cyclograms
Statistics in Medicine, Volume 45, Issue 18-19, August 2026.ABSTRACT In several biomedical contexts, the need for diagnostic analyses of data that is a set of directions in 2, 3, or higher dimensions arises, as for instance, when considering the relative movement of body parts like the limbs, or looking at anatomical orientations.
S. Rao Jammalamadaka, Ali H. Abuzaid
wiley +1 more source
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 ...
A. Blaga, Antonella Nannicini
semanticscholar +1 more source