Results 61 to 70 of about 33,238 (212)
ADDITIVE GROUPS OF ASSOCIATIVE RINGS
Научный 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
Minimal projective varieties satisfying Miyaoka's equality
Proceedings of the London Mathematical Society, Volume 131, Issue 6, December 2025.Abstract In this paper, we establish a structure theorem for a minimal projective klt variety X$X$ satisfying Miyaoka's equality 3c2(X)=c1(X)2$3c_2(X) = c_1(X)^2$. Specifically, we prove that the canonical divisor KX$K_X$ is semi‐ample and that the Kodaira dimension κ(KX)$\kappa (K_X)$ is equal to 0, 1, or 2. Furthermore, based on this abundance result,
Masataka Iwai +2 more
wiley +1 more source
Holonomy Groups of Complete Flat Pseudo-Riemannian Homogeneous Spaces
, 2012 We show that a complete flat pseudo-Riemannian homogeneous manifold with non-abelian linear holonomy is of dimension at least 14. Due to an example constructed in a previous article by Oliver Baues and the author, this is a sharp bound.
Baues +8 more
core +1 more source
Symmetric products and puncturing Campana‐special varieties
Proceedings of the London Mathematical Society, Volume 131, Issue 6, December 2025.Abstract We give a counterexample to the Arithmetic Puncturing Conjecture and Geometric Puncturing Conjecture of Hassett–Tschinkel using symmetric powers of uniruled surfaces, and propose a corrected conjecture inspired by Campana's conjectures on special varieties.
Finn Bartsch +2 more
wiley +1 more source
Torsion-free, divisible, and Mittag-Leffler modules [PDF]
, 2013 We study (relative) K-Mittag-Leffler modules, with emphasis on the class K of absolutely pure modules. A final goal is to describe the K-Mittag-Leffler abelian groups as those that are, modulo their torsion part, aleph_1-free, Cor.6.12.
Philipp Rothmaler, To Leonell
core
Localizations of torsion-free abelian groups II
Journal of Algebra, 2005 A homomorphism \(\alpha\colon A\to B\) between Abelian groups \(A,B\) is called a localization of \(A\) if every homomorphism \(\varphi\) from \(A\) to \(B\) has a unique extension to an endomorphism \(\psi\) of \(B\) in the sense that \(\varphi=\psi\circ\alpha\).
openaire +2 more sources
Separable torsion-free abelian E∗-groups
Journal 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
GL‐algebras in positive characteristic II: The polynomial ring
Proceedings of the London Mathematical Society, Volume 131, Issue 6, December 2025.Abstract We study GL$\mathbf {GL}$‐equivariant modules over the infinite variable polynomial ring S=k[x1,x2,…,xn,…]$S = k[x_1, x_2, \ldots, x_n, \ldots]$ with k$k$ an infinite field of characteristic p>0$p > 0$. We extend many of Sam–Snowden's far‐reaching results from characteristic zero to this setting.
Karthik Ganapathy
wiley +1 more source
Higher homotopy of groups definable in o-minimal structures
, 2009 It is known that a definably compact group G is an extension of a compact Lie group L by a divisible torsion-free normal subgroup. We show that the o-minimal higher homotopy groups of G are isomorphic to the corresponding higher homotopy groups of L.
Berarducci, Alessandro +2 more
core +2 more sources
Algorithms in Direct Decompositions of Torsion-Free Abelian Groups [PDF]
, 2023 E. A. Blagoveshchenskaya +1 more
openalex +1 more source