Results 71 to 80 of about 2,910 (192)

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

Characterizing Affine Vector Fields on Pseudo-Riemannian Manifolds

Axioms
We study the characteristics of affine vector fields on pseudo-Riemannian manifolds and provide tensorial formulas that characterize these vector fields.
Norah Alshehri, Mohammed Guediri
doaj   +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

Volcanic Eruptions Reorganize Climate Teleconnections: Detection via Riemannian Covariance Fingerprinting

Geophysical Research Letters, Volume 53, Issue 15, 16 August 2026.
Abstract Standard detection and attribution of volcanic forcing targets spatial temperature anomalies. We show that the covariance structure of climate variability carries an independent volcanic fingerprint. Applying tangent‐space regression on the symmetric positive definite manifold SPD(8) to 40 years of eight teleconnection indices, we detect ...
Sloan Austermann
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, Edgar Solomonik, Xiaoye Sherry Li, Yang Liu   +3 more
wiley   +1 more source

Conformal quasi-hemi-slant $\xi^{\perp}$-Riemannian submersions from Sasakian manifolds [PDF]

Mathematica Bohemica
We introduce some geometric properties of a horizontally conformal quasi-hemi-slant Riemannian submersion from a Sasakian manifold, normal to the characteristic vector field, supported by an example.
Fortuné Massamba, Pontsho Moile
doaj   +1 more source

Boundary‐Only Weak Deflection by Regular Black Holes, Black‐Bounces, Wormholes, and Static Quadrupolar Spacetimes

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

Adaptive filter with Riemannian manifold constraint. [PDF]

Sci Rep, 2023
Mejia J, Mederos B, Gordillo N, Ortega L.   +3 more
europepmc   +1 more source