Results 21 to 30 of about 238 (157)

Solving logistic tasks by parallelizing algorithms of the theory of direct decompositions of torsion-free abelian groups [PDF]

open access: yesE3S Web of Conferences, 2023
The paper considers the principles of parallelization at marshalling yards and determines their importance. There are presented the methods for direct decompositions of torsion-free Abelian groups of finite rank.
Blagoveshchenskaya E.   +2 more
doaj   +1 more source

Structure of Finite-Dimensional Protori

open access: yesAxioms, 2019
A Structure Theorem for Protori is derived for the category of finite-dimensional protori (compact connected abelian groups), which details the interplay between the properties of density, discreteness, torsion, and divisibility within a finite ...
Wayne Lewis
doaj   +1 more source

A Note on Additive Groups of Some Specific Torsion-Free Rings of Rank Three and Mixed Associative Rings

open access: yesDiscussiones Mathematicae - General Algebra and Applications, 2017
It is studied how rank two pure subgroups of a torsion-free Abelian group of rank three influences its structure and type set. In particular, the criterion for such a subgroup B to be a direct summand of a torsion-free Abelian group of rank three with ...
Najafizadeh Alireza, Woronowicz Mateusz
doaj   +1 more source

Groups with minimax commutator subgroup [PDF]

open access: yesInternational 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  

Local equivalence and refinements of Rasmussen's s‐invariant

open access: yesJournal of Topology, Volume 19, Issue 1, March 2026.
Abstract Inspired by the notions of local equivalence in monopole and Heegaard Floer homology, we introduce a version of local equivalence that combines odd Khovanov homology with equivariant even Khovanov homology into an algebraic package called a local even–odd (LEO) triple.
Nathan M. Dunfield   +2 more
wiley   +1 more source

Countable ℵ0-indecomposable mixed abelian groups of finite torsion-free rank

open access: yesJournal of Algebra, 1986
A group is \(\aleph_ 0\)-indecomposable if it cannot be decomposed into a direct sum of \(\aleph_ 0\) non-zero summands. In this paper the authors find necessary and sufficient conditions for an extension of a countable reduced torsion abelian group T by a finite rank torsion-free abelian group R to be \(\aleph_ 0\)-indecomposable. These conditions are
Shelah, Saharon, Soifer, Alexander
openaire   +2 more sources

Witten genera of complete intersections

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 2, February 2026.
Abstract We prove vanishing results for Witten genera of string generalized complete intersections in homogeneous Spinc$\text{Spin}^c$‐manifolds and in other Spinc$\text{Spin}^c$‐manifolds with Lie group actions. By applying these results to Fano manifolds with second Betti number equal to one we get new evidence for a conjecture of Stolz.
Michael Wiemeler
wiley   +1 more source

On the topological ranks of Banach ∗$^*$‐algebras associated with groups of subexponential growth

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 2, February 2026.
Abstract Let G$G$ be a group of subexponential growth and C→qG$\mathcal C\overset{q}{\rightarrow }G$ a Fell bundle. We show that any Banach ∗$^*$‐algebra that sits between the associated ℓ1$\ell ^1$‐algebra ℓ1(G|C)$\ell ^1(G\,\vert \,\mathcal C)$ and its C∗$C^*$‐envelope has the same topological stable rank and real rank as ℓ1(G|C)$\ell ^1(G\,\vert ...
Felipe I. Flores
wiley   +1 more source

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