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Related papers: Infinitesimal index: cohomology computations

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We investigate the homological behaviour of compactly generated triangulated categories under separable extensions. We show that homological invariants (finiteness of global dimension, gorensteinness and regularity) are preserved under such…

Representation Theory · Mathematics 2026-04-21 Miltiadis Karakikes , Panagiotis Kostas

Syntomic cohomology here defined yields a link between rigid cohomology and etale cohomology, viewing the last one as the fixed points under Frobenius of the former one. Let V be a complete discrete valuation ring, with perfect residue…

Algebraic Geometry · Mathematics 2009-10-26 Jean-Yves Etesse

We develop a fundamental theory of compact quantum group equivariant finite extensions of C*-algebras. In particular we focus on the case of quantum homogeneous spaces and give a Tannaka-Krein type result for equivariant correspondences. As…

Operator Algebras · Mathematics 2023-01-13 Mao Hoshino

We compute the invariant subspace of the rational group ring of a surface, truncated by powers of the augmentation ideal, under the action of the mapping class group. The surface is compact, oriented with one boundary component. This…

Geometric Topology · Mathematics 2025-10-02 Andreas Stavrou

We use cross ratios to describe second real continuous bounded cohomology for locally compact topological groups. We also derive a rigidity result for cocycles with values in the isometry group of a proper hyperbolic geodesic metric space.

Group Theory · Mathematics 2007-05-23 Ursula Hamenstaedt

A logarithm representation of operators is introduced as well as a concept of pre-infinitesimal generator. Generators of invertible evolution families are represented by the logarithm representation, and a set of operators represented by…

Functional Analysis · Mathematics 2018-05-03 Yoritaka Iwata

We study the infinitesimal rigidity of equivariant minimal maps from the universal cover of a smooth oriented surface (possibly non-compact) into a Riemannian symmetric space, focusing on representations arising from cyclic harmonic…

Differential Geometry · Mathematics 2026-05-12 Qiongling Li , Junming Zhang

This paper concerns the computation and identification of the (homological) Conley index over the integers, in the context of discrete dynamical systems generated by continuous maps. We discuss the significance with respect to nonlinear…

Dynamical Systems · Mathematics 2023-03-14 Konstantin Mischaikow , Charles Weibel

We study the limiting behavior of extremal cohomology groups of $k$-points configuration spaces of complex projective spaces of complex dimension $m\geq 4.$ In the previous work, we prove that the extremal cohomology groups of degrees…

Algebraic Topology · Mathematics 2022-11-01 Muhammad Yameen

Equivariance has emerged as a desirable property of representations of objects subject to identity-preserving transformations that constitute a group, such as translations and rotations. However, the expressivity of a representation…

Machine Learning · Computer Science 2022-02-08 Matthew Farrell , Blake Bordelon , Shubhendu Trivedi , Cengiz Pehlevan

We present a simple proof of a precise version of the localization theorem in equivariant cohomology. As an application, we describe the cohomology algebra of any compact symplectic variety with a multiplicity-free action of a compact Lie…

dg-ga · Mathematics 2007-05-23 Michel Brion , Michèle Vergne

Symmetric cohomology of groups, defined by M. Staic in [2], is similar to the way one defines the cyclic cohomology for algebras. We show that there is a well-defined restriction, conjugation and transfer map in symmetric cohomology, which…

Group Theory · Mathematics 2014-12-08 C. C. Todea

Groups with a non-cyclic Sylow $p$-subgroup have too many representations over a field of characteristic~$p$ to describe them fully. A~natural question arises, whether the world of representations coming from algebraic varieties with a…

Algebraic Geometry · Mathematics 2024-10-07 Jędrzej Garnek

We give precise estimates of some holomorphically invariant infinitesimal metrics near a pseudoconcave points in a wide family of ``model'' domains for that situation in $\mathbb C^2$. This extends to metrics (rather distances) the authors'…

Complex Variables · Mathematics 2026-05-05 Pascal J. Thomas , Nikolai Nikolov

Complex braid groups are the natural generalizations of braid groups associated to arbitrary (finite) complex reflection groups. We investigate several methods for computing the homology of these groups. In particular, we get the Poincar\'e…

Algebraic Topology · Mathematics 2010-11-22 Filippo Callegaro , Ivan Marin

Following our previous work, we develop an algorithm to compute a presentation of the fundamental group of certain partial compactifications of the complement of a complex arrangement of lines in the projective plane. It applies, in…

Algebraic Geometry · Mathematics 2021-09-09 Rodolfo Aguilar Aguilar

The results of a previous paper on the equivariant homotopy theory of crossed complexes are generalised from the case of a discrete group to general topological groups. The principal new ingredient necessary for this is an analysis of…

Algebraic Topology · Mathematics 2016-08-15 R Brown , M Golasiński , T Porter , A Tonks

In this note we present a formula for the equivariant index of the cohomological complex obtained from localization of $\mathcal{N}=2$ SYM on simply-connected compact four-manifolds with a $T^2$-action. Knowledge of said index is essential…

High Energy Physics - Theory · Physics 2022-09-20 Roman Mauch , Lorenzo Ruggeri

This work deals with relations between a bounded cohomological invariant and the geometry of Hermitian symmetric spaces of noncompact type. The invariant, obtained from the K\"ahler class, is used to define and characterize a special class…

Differential Geometry · Mathematics 2007-05-23 Anna Wienhard

This paper presents new research in infinitesimal algebra by introducing the concept of an infinitesimal group and exploring its properties and ramifications. The author investigates first- and second-order subgroups of Lie groups and…

Differential Geometry · Mathematics 2023-05-09 Filip Bár