Results 51 to 60 of about 35,842 (169)

Automorphisms and dilation theory of triangular UHF algebras

open access: yes, 2013
We study the triangular subalgebras of UHF algebras which provide new examples of algebras with the Dirichlet property and the Ando property. This in turn allows us to describe the semicrossed product by an isometric automorphism.
Ramsey, Christopher
core   +1 more source

TORSION-FREE WEAKLY TRANSITIVE ABELIAN GROUPS

open access: yesCommunications in Algebra, 2005
ABSTRACT We introduce the notion of weak transitivity for torsion-free abelian groups. A torsion-free abelian group G is called weakly transitive if for any pair of elements x, y ∈ G and endomorphisms ϕ, ψ ∈ End(G) such that xϕ = y, yψ = x, there exists an automorphism of G mapping x onto y.
Goldsmith, Brendan, Strungmann, Lutz
openaire   +4 more sources

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

open access: yesJournal 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

Separable torsion-free abelian E∗-groups

open access: yesJournal of Pure and Applied Algebra, 1998
The first half of this paper characterizes the torsion-free separable abelian groups \(G\) whose endomorphism semigroup \(E(G)^*\) admits a unique addition; that is, the endomorphism ring \(E(G)\) is isomorphic to any ring \(S\) for which \(E(G)^*\) is isomorphic to \(S^*\).
Lubimcev, O.   +2 more
openaire   +1 more source

Ordinary primes for GL2$\operatorname{GL}_2$‐type abelian varieties and weight 2 modular forms

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract Let A$A$ be a g$g$‐dimensional abelian variety defined over a number field F$F$. It is conjectured that the set of ordinary primes of A$A$ over F$F$ has positive density, and this is known to be true when g=1,2$g=1, 2$, or for certain abelian varieties with extra endomorphisms.
Tian Wang, Pengcheng Zhang
wiley   +1 more source

Vector bundles on bielliptic surfaces: Ulrich bundles and degree of irrationality

open access: yesMathematische Nachrichten, Volume 299, Issue 3, Page 514-528, March 2026.
Abstract This paper deals with two problems about vector bundles on bielliptic surfaces. The first is to give a classification of Ulrich bundles on such surfaces S$S$, which depends on the topological type of S$S$. In doing so, we study the weak Brill–Noether property for moduli spaces of sheaves with isotropic Mukai vector. Adapting an idea of Moretti
Edoardo Mason
wiley   +1 more source

ADDITIVE GROUPS OF ASSOCIATIVE RINGS

open access: yesНаучный вестник МГТУ ГА, 2016
An abelian group is said to be semisimple if it is an additive group of at least one semisimple associative ring. It is proved that the description problem for semisimple groups is reduced to the case of reduced groups. As a consequence, it is shown that
E. I. Kompantseva
doaj  

A Re‐Examination of Foundational Elements of Cosmology

open access: yesFortschritte der Physik, Volume 74, Issue 3, March 2026.
ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
wiley   +1 more source

On Algebraic and Definable Closures for Theories of Abelian Groups

open access: yesИзвестия 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

Decompositions of torsion-free abelian groups [PDF]

open access: yesJournal of Algebra, 2019
All groups in this review are abelian and torsion-free. Some concepts like near-isomorphism, sufficient-isomorphism, mono-equivalence, main decomposition, the length of a decomposition, strongly-separable groups, quasi-separable groups, \(\tau\)-homogeneous groups, \(\tau\)-clipped groups for any type \(\tau\) and various kinds of types have been ...
Gábor Braun   +2 more
openaire   +2 more sources

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