Results 71 to 80 of about 4,558 (244)

Dynamics and the Cohomology of Measured Laminations

Mathematics, 2016
In this paper, the interconnection between the cohomology of measured group actions and the cohomology of measured laminations is explored, the latter being a generalization of the former for the case of discrete group actions and cocycles evaluated on ...
Carlos Meniño Cotón
doaj   +1 more source

Mirror symmetry, Laurent inversion, and the classification of Q$\mathbb {Q}$‐Fano threefolds

Transactions of the London Mathematical Society, Volume 12, Issue 1, December 2025.
Abstract We describe recent progress in a program to understand the classification of three‐dimensional Fano varieties with Q$\mathbb {Q}$‐factorial terminal singularities using mirror symmetry. As part of this we give an improved and more conceptual understanding of Laurent inversion, a technique that sometimes allows one to construct a Fano variety X$
Tom Coates, Liana Heuberger, Alexander M. Kasprzyk   +2 more
wiley   +1 more source

Modification and the cohomology groups of compact solvmanifolds Ⅱ

Electronic Research Archive
In this article, we refine the modification theorem for a compact solvmanifold given in 2006 and completely solve the problem of finding the cohomology ring on compact solvmanifolds.
Daniel Guan
doaj   +1 more source

FREE FINITE GROUP ACTIONS ON RATIONAL HOMOLOGY 3-SPHERES

Forum of Mathematics, Sigma, 2019
We use methods from the cohomology of groups to describe the finite groups which can act freely and homologically trivially on closed 3-manifolds which are rational homology spheres.
ALEJANDRO ADEM, IAN HAMBLETON
doaj   +1 more source

STABILITY, COHOMOLOGY VANISHING, AND NONAPPROXIMABLE GROUPS

Forum of Mathematics, Sigma, 2020
Several well-known open questions (such as: are all groups sofic/hyperlinear?) have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups $\text{Sym}(n)$ (in the sofic case) or the finite-dimensional unitary ...
MARCUS DE CHIFFRE, LEV GLEBSKY, ALEXANDER LUBOTZKY, ANDREAS THOM   +3 more
doaj   +1 more source

Real models for the framed little n$n$‐disks operads

Journal of Topology, Volume 18, Issue 4, December 2025.
Abstract We study the action of the orthogonal group on the little n$n$‐disks operads. As an application we provide small models (over the reals) for the framed little n$n$‐disks operads. It follows in particular that the framed little n$n$‐disks operads are formal (over the reals) for n$n$ even and coformal for all n$n$.
Anton Khoroshkin, Thomas Willwacher
wiley   +1 more source

Parametrized stability and the universal property of global spectra

Journal of Topology, Volume 18, Issue 4, December 2025.
Abstract We develop a framework of parametrized semiadditivity and stability with respect to so‐called atomic orbital subcategories of an indexing ∞$\infty$‐category T$T$, extending work of Nardin. Specializing this framework, we introduce global ∞$\infty$‐categories and the notions of equivariant semiadditivity and stability, yielding a higher ...
Bastiaan Cnossen, Tobias Lenz, Sil Linskens   +2 more
wiley   +1 more source

Floer theory for the variation operator of an isolated singularity

Journal of Topology, Volume 18, Issue 4, December 2025.
Abstract The variation operator in singularity theory maps relative homology cycles to compact cycles in the Milnor fiber using the monodromy. We construct its symplectic analog for an isolated singularity. We define the monodromy Lagrangian Floer cohomology, which provides categorifications of the standard theorems on the variation operator and the ...
Hanwool Bae, Cheol‐Hyun Cho, Dongwook Choa, Wonbo Jeong   +3 more
wiley   +1 more source

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
wiley   +1 more source

On 2-form gauge models of topological phases

Journal of High Energy Physics, 2019
We explore 2-form topological gauge theories in (3+1)d. These theories can be constructed as sigma models with target space the second classifying space B 2 G of the symmetry group G, and they are classified by cohomology classes of B 2 G.
Clement Delcamp, Apoorv Tiwari
doaj   +1 more source