Results 81 to 90 of about 46,642 (242)
Algorithms in Direct Decompositions of Torsion-Free Abelian Groups [PDF]
, 2023 E. A. Blagoveshchenskaya +1 more
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TORSION-FREE WEAKLY TRANSITIVE ABELIAN GROUPS
Communications 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
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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
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E-transitive torsion-free abelian groups
Journal of Algebra, 1987 The author extends the well-known notion of a strongly homogeneous group G, an abelian group with Aut G acting transitively on the pure rank-one subgroups of G, to E-transitive groups. In this case the endomorphism ring \(E=End G\) acts transitive on the pure rank-one subgroups.
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Uniquely Transitive Torsion-Free Abelian Groups
, 2004 We will answer a question raised by Emmanuel Dror Farjoun concerning the existence of torsion-free abelian groups G such that for any ordered pair of pure elements there is a unique automorphism mapping the first element onto the second one. We will show the existence of such a group of cardinality lambda for any successor cardinal lambda=mu^+ with mu ...
Göbel, Rüdiger, Shelah, Saharon
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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
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On the Abelianization of a Torsion Free Crystallographic Group
Jurnal Teknologi, 2014 A torsion free crystallographic group, which is also known as a Bieberbach group is a generalization of free abelian groups. It is an extension of a lattice group by a finite point group. The study of n-dimensional crystallographic group had been done by many researchers over a hundred years ago.
Mohd. Idrus, Nor'ashiqin +3 more
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Cohomotopy sets of (n−1)$(n-1)$‐connected (2n+2)$(2n+2)$‐manifolds for small n$n$
Transactions of the London Mathematical Society, Volume 12, Issue 1, December 2025.Abstract Let M$M$ be a closed orientable (n−1)$(n-1)$‐connected (2n+2)$(2n+2)$‐manifold, n⩾2$n\geqslant 2$. In this paper, we combine the Postnikov tower of spheres and the homotopy decomposition of the reduced suspension space ΣM$\Sigma M$ to investigate the (integral) cohomotopy sets π*(M)$\pi ^\ast (M)$ for n=2,3,4$n=2,3,4$, under the assumption ...
Pengcheng Li, Jianzhong Pan, Jie Wu
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Topological K‐theory of quasi‐BPS categories for Higgs bundles
Journal of Topology, Volume 18, Issue 4, December 2025.Abstract In a previous paper, we introduced quasi‐BPS categories for moduli stacks of semistable Higgs bundles. Under a certain condition on the rank, Euler characteristic, and weight, the quasi‐BPS categories (called BPS in this case) are noncommutative analogues of Hitchin integrable systems.
Tudor Pădurariu, Yukinobu Toda
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On the section conjecture over fields of finite type
Mathematische Nachrichten, Volume 298, Issue 11, Page 3476-3493, November 2025.Abstract Assume that the section conjecture holds over number fields. We prove then that it holds for a broad class of curves defined over finitely generated extensions of Q$\mathbb {Q}$. This class contains every projective, hyperelliptic curve, every hyperbolic, affine curve of genus ≤2$\le 2$, and a basis of open subsets of any curve.
Giulio Bresciani
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