Results 51 to 60 of about 4,558 (244)
Combination of open covers with π1$\pi _1$‐constraints
Bulletin of the London Mathematical Society, Volume 57, Issue 12, Page 3886-3901, December 2025.Abstract Let G$G$ be a group and let F$\mathcal {F}$ be a family of subgroups of G$G$. The generalised Lusternik–Schnirelmann category catF(G)$\operatorname{cat}_\mathcal {F}(G)$ is the minimal cardinality of covers of BG$BG$ by open subsets with fundamental group in F$\mathcal {F}$.
Pietro Capovilla, Kevin Li, Clara Löh
wiley +1 more source
Substitutions with Vanishing Rotationally Invariant First Cohomology
Discrete Dynamics in Nature and Society, 2012 The cohomology groups of tiling spaces with three-fold and nine-fold symmetries are obtained. The substitution tilings are characterized by the fact that they have vanishing first cohomology group in the space of tilings modulo a rotation.
Juan García Escudero
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Polarization and Gorenstein liaison
Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.Abstract A major open question in the theory of Gorenstein liaison is whether or not every arithmetically Cohen–Macaulay subscheme of Pn$\mathbb {P}^n$ can be G‐linked to a complete intersection. Migliore and Nagel showed that if such a scheme is generically Gorenstein (e.g., reduced), then, after re‐embedding so that it is viewed as a subscheme of Pn ...
Sara Faridi +3 more
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The shift‐homological spectrum and parametrising kernels of rank functions
Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.Abstract For any compactly generated triangulated category, we introduce two topological spaces, the shift spectrum and the shift‐homological spectrum. We use them to parametrise a family of thick subcategories of the compact objects, which we call radical.
Isaac Bird +2 more
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Iitaka fibrations and integral points: A family of arbitrarily polarized spherical threefolds
Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.Abstract Studying Manin's program for a family of spherical log Fano threefolds, we determine the asymptotic number of integral points whose height associated with an arbitrary ample line bundle is bounded. This confirms a recent conjecture by Santens and sheds new light on the logarithmic analog of Iitaka fibrations, which have not yet been adequately
Ulrich Derenthal, Florian Wilsch
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Local–global principles for semi‐integral points on Markoff orbifold pairs
Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.Abstract We study local–global principles for semi‐integral points on orbifold pairs of Markoff type. In particular, we analyse when these orbifold pairs satisfy weak weak approximation, weak approximation and strong approximation off a finite set of places.
Vladimir Mitankin, Justin Uhlemann
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HILBERT STRATIFOLDS AND A QUILLEN TYPE GEOMETRIC DESCRIPTION OF COHOMOLOGY FOR HILBERT MANIFOLDS
Forum of Mathematics, Sigma, 2018 In this paper we use tools from differential topology to give a geometric description of cohomology for Hilbert manifolds. Our model is Quillen’s geometric description of cobordism groups for finite-dimensional smooth manifolds [Quillen, ‘Elementary ...
MATTHIAS KRECK, HAGGAI TENE
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On the solvability of the Lie algebra HH1(B)$\mathrm{HH}^1(B)$ for blocks of finite groups
Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.Abstract We give some criteria for the Lie algebra HH1(B)$\mathrm{HH}^1(B)$ to be solvable, where B$B$ is a p$p$‐block of a finite group algebra, in terms of the action of an inertial quotient of B$B$ on a defect group of B$B$.
Markus Linckelmann, Jialin Wang
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First and second cohomology group of a bu ndle
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2012 Let (E, π, M) be a vector bundle. We define two cohomology groups associated to π using the first and second order jet manifolds of this bundle. We prove that one of them is isomorphic with a Čech cohomology group of the base space.
Manea Adelina
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On cohomology isomorphisms of groups
Journal of Algebra, 2007 The author proves the following theorem for a wide class of groups including finite groups, compact Lie groups, groups of finite virtual cohomological dimension over \(\mathbb{F}_p\) and profinite groups. Theorem. Let \(f\colon H\to G\) be a homomorphism such that the induced map \(f^*\colon H^*(G;\mathbb{F}_p)\to H^*(H;\mathbb{F}_p)\) is an ...
openaire +3 more sources