Results 41 to 50 of about 33,164 (164)

Which singular tangent bundles are isomorphic?

Journal of the London Mathematical Society, Volume 113, Issue 5, May 2026.
Abstract Logarithmic and b$ b$‐tangent bundles provide a versatile framework for addressing singularities in geometry. Introduced by Deligne and Melrose, these modified bundles resolve singularities by reframing singular vector fields as well‐behaved sections of these singular bundles.
Eva Miranda, Pablo Nicolás
wiley   +1 more source

Groups with minimax commutator subgroup [PDF]

International Journal of Group Theory, 2014
A result of Dixon, Evans and Smith shows that if $G$ is a locally (soluble-by-finite) group whose proper subgroups are (finite rank)-by-abelian, then $G$ itself has this property, i.e. the commutator subgroup of~$G$ has finite rank.
Francesco de Giovanni, Trombetti
doaj  

The $L^2$-torsion polytope of amenable groups

, 2018
We introduce the notion of groups of polytope class and show that torsion-free amenable groups satisfying the Atiyah Conjecture possess this property. A direct consequence is the homotopy invariance of the $L^2$-torsion polytope among $G$-CW-complexes ...
Funke, Florian
core   +1 more source

Lorentzian homogeneous structures with indecomposable holonomy

Journal of the London Mathematical Society, Volume 113, Issue 5, May 2026.
Abstract For a Lorentzian homogeneous space, we study how algebraic conditions on the isotropy group affect the geometry and curvature of the homogeneous space. More specifically, we prove that a Lorentzian locally homogeneous space is locally isometric to a plane wave if it admits an Ambrose–Singer connection with indecomposable, non‐irreducible ...
Steven Greenwood, Thomas Leistner
wiley   +1 more source

Strictly positive definite functions on compact abelian groups

, 2010
We study the Fourier characterisation of strictly positive definite functions on compact abelian groups. Our main result settles the case $G = F \times \mathbb{T}^r$, with $r \in \mathbb{N}$ and $F$ finite.
Emonds, Jan, Fuehr, Hartmut
core   +1 more source

Electric‐Current‐Assisted Nucleation of Zero‐Field Hopfion Rings

Advanced Materials, Volume 38, Issue 21, 13 April 2026.
This work reports a novel and efficient nucleation protocol for 3D localized topological magnetic solitons‐hopfion rings in chiral magnets using pulsed electric currents. By using Lorentz transmission electron microscopy and topological analysis, we report characteristic features and extraordinary stability of hopfion rings in zero or inverted external
Xiaowen Chen, Dongsheng Song, Filipp N. Rybakov, Nikolai S. Kiselev, Long Li, Wen Shi, Rui Wu, Xuewen Fu, Olle Eriksson, Stefan Blügel, Rafal E. Dunin‐Borkowski, Haifeng Du, Fengshan Zheng   +12 more
wiley   +1 more source

A torsion theory in the category of cocommutative Hopf algebras

, 2015
The purpose of this article is to prove that the category of cocommutative Hopf $K$-algebras, over a field $K$ of characteristic zero, is a semi-abelian category.
Gran, Marino, Kadjo, Gabriel, Vercruysse, Joost   +2 more
core   +1 more source

Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the String‐Theoretical Swampland Programme

Fortschritte der Physik, Volume 74, Issue 4, April 2026.
Abstract String theory has strong implications for cosmology, implying the absence of a cosmological constant, ruling out single‐field slow‐roll inflation, and that black holes decay. The origins of these statements are elucidated within the string‐theoretical swampland programme.
Kay Lehnert
wiley   +1 more source

A Miyaoka–Yau inequality for hyperplane arrangements in CPn$\mathbb {CP}^n$

Journal of the London Mathematical Society, Volume 113, Issue 4, April 2026.
Abstract Let H$\mathcal {H}$ be a hyperplane arrangement in CPn$\mathbb {CP}^n$. We define a quadratic form Q$Q$ on RH$\mathbb {R}^{\mathcal {H}}$ that is entirely determined by the intersection poset of H$\mathcal {H}$. Using the Bogomolov–Gieseker inequality for parabolic bundles, we show that if a∈RH$\mathbf {a}\in \mathbb {R}^{\mathcal {H}}$ is ...
Martin de Borbon, Dmitri Panov
wiley   +1 more source

On Algebraic and Definable Closures for Theories of Abelian Groups

Известия Иркутского государственного университета: Серия "Математика"
Classifying abelian groups and their elementary theories, a series of characteristics arises that describe certain features of the objects under consideration.
In.I. Pavlyuk
doaj   +1 more source