Results 71 to 80 of about 1,842 (194)

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

Contact Semi-Riemannian Structures in CR Geometry: Some Aspects

Axioms, 2019
There is one-to-one correspondence between contact semi-Riemannian structures ( η , ξ , φ , g ) and non-degenerate almost CR structures ( H , ϑ , J ) .
Domenico Perrone
doaj   +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

An Equivalence Theorem and A Sequential Algorithm for A-Optimal Experimental Designs on Manifolds

Axioms
Selecting input data points in the context of high-dimensional, nonlinear, and complex data in Riemannian space is challenging. While optimal experimental design theory is well-established in Euclidean space, its extension to Riemannian manifolds remains
Jingwen Zhang, Yaping Wang
doaj   +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

Commutative curvature operators over four-dimensional generalized symmetric

Sahand Communications in Mathematical Analysis, 2014
Commutative properties of four-dimensional generalized symmetric pseudo-Riemannian manifolds were considered. Specially, in this paper, we studied Skew-Tsankov and Jacobi-Tsankov conditions in 4-dimensional pseudo-Riemannian generalized symmetric ...
Ali Haji-Badali, Masoud Dehghan, Fereshteh Nourmohammadi   +2 more
doaj  

The Morse Index of Sacks–Uhlenbeck α-Harmonic Maps for Riemannian Manifolds

Journal of Mathematics
In this paper, first we prove a nonexistence theorem for α-harmonic mappings between Riemannian manifolds. Second, the instability of nonconstant α-harmonic maps is studied with regard to the Ricci curvature criterion of their codomain. Then, we estimate
Amir Shahnavaz, Nader Kouhestani, Seyed Mehdi Kazemi Torbaghan   +2 more
doaj   +1 more source

Property of the curvatures of integrable poly-Norden manifolds and their submanifolds [PDF]

Journal of Mahani Mathematical Research
In the present paper, almost poly-Norden and locally almost poly-Norden manifolds are investigated. Ricci tensor and Riemannian curvature of integrable poly-Norden manifolds are studied. Geometric properties of   submanifolds of these types of  manifolds
Masoumeh Tofighi, Mohammad Bagher Kazemi Balgeshir   +1 more
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