Results 11 to 20 of about 164 (135)
Strongly homogeneous torsion free abelian groups of finite rank [PDF]
Proceedings of the American Mathematical Society, 1976 An abelian group is strongly homogeneous if for any two pure rank 1 subgroups there is an automorphism sending one onto the other. Finite rank torsion free strongly homogeneous groups are characterized as the tensor product of certain subrings of algebraic number fields with finite direct ...
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On the structure of one-generated Leibniz rings
Researches in MathematicsThe paper is devoted to the study of one-generated Leibniz rings. We begin with a short discussion of the relation between Lie rings, Lie algebras, Leibniz algebras, and Leibniz rings, and recall the basic notions needed in the sequel.
L.A. Kurdachenko +2 more
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Dualities for torsion-free abelian groups of finite rank
Journal of Algebra, 1990 All groups considered here are torsion-free abelian groups of finite rank. Let F be a full free subgroup of such a group G. The finite outer type of G, FOT(G), is \((...,\pi_ p,...)\), where \(p^{\pi_ p}\) is the order of a maximal cyclic summand in the p-component of the reduced part of G/F.
Vinsonhaler, C, Wickless, W
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The Two Extremal Rays of Some Hyper–Kähler Fourfolds
Mathematische Nachrichten, EarlyView.ABSTRACT We consider projective Hyper–Kähler manifolds of dimension 4 that are deformation equivalent to Hilbert squares of K3 surfaces. In case such a manifold admits a divisorial contraction, the exceptional divisor is a conic bundle over a K3 surface. A classification of lattice embeddings implies that there are five types of such conic bundles.
Federica Galluzzi, Bert van Geemen
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Context‐free graphs and their transition groups
Transactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.Abstract Starting from context‐free inverse graphs, we introduce a new class of groups and study their structural properties. We establish closure properties, show that their coword problems are context‐free, analyze torsion elements, and realize them as subgroups of the asynchronous rational group.
Daniele D'Angeli +3 more
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Kitaoka's conjecture and sums of squares
Bulletin of the London Mathematical Society, Volume 58, Issue 8, August 2026.Abstract We connect the existence of a ternary classical universal quadratic form over a totally real number field K$K$ with the property that all totally positive multiples of 2 are sums of squares (if K$K$ does not contain 2$\sqrt{2}$ or contains a nonsquare totally positive unit).
Vítězslav Kala +2 more
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The cotypeset of a torsion-free Abelian group of finite rank
Journal of Algebra, 1983 For a discussion of types and for basic definitions and notations see [ 7 1. In 1961 Beaumont and Pierce [4] posed the problem of finding necessary and sufficient conditions for a (necessarily finite or countable) set T of types to be realized as T = typeset G for some G of rank two.
Vinsonhaler, C, Wickless, W.J
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Groups with a finite Busemann boundary are virtually cyclic
Bulletin of the London Mathematical Society, Volume 58, Issue 8, August 2026.Abstract This note is a continuation of the study of the relationship between the geometry of Cayley graphs and the size of its metric‐functional boundary. We show that if there exists a Cayley graph with finitely many Busemann points, then the underlying group is virtually cyclic.
Corentin Bodart +2 more
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Cohomology of solvable saturable pro‐p$p$ groups and Lie algebras
Bulletin of the London Mathematical Society, Volume 58, Issue 7, July 2026.Abstract Let p$p$ be an odd prime and let n∈N$n\in \mathbb {N}$ be an integer. We show that the n-th$n{\text{-th}}$ mod‐p$p$ cohomology of a solvable saturable pro‐p$p$ group is isomorphic to the n-th$n{\text{-th}}$ mod‐p$p$ cohomology of its associated Zp$\mathbb {Z}_p$‐Lie algebra g$\mathfrak {g}$ as an Fp$\mathbb {F}_p$‐vector space.
Oihana Garaialde Ocaña +2 more
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An equivalence relation for torsion-free abelian groups of finite rank
Journal of Algebra, 1992 The equivalence relation in question is defined as follows: let \({^\perp G}=\{X:\Hom(X,G)=0\}\). Then \(G\) is equivalent to \(H\) if and only if \({^\perp G}={^\perp H}\). Since this relation is coarser than quasi-isomorphism, it is useful in classifying torsion-free abelian groups.
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