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We uncover several general phenomenas governing functor homology over additive categories. In particular, we generalize the strong comparison theorem of Franjou Friedlander Scorichenko and Suslin to the setting of Fp-linear additive…

Algebraic Topology · Mathematics 2022-11-08 Aurélien Djament , Antoine Touzé

We discuss how the Hochschild cohomology of a dg category can be computed as the trace of its Serre functor. Applying this approach to the principal block of the Bernstein--Gelfand--Gelfand category $\mathcal{O}$, we obtain its Hochschild…

Representation Theory · Mathematics 2020-12-07 Clemens Koppensteiner

In this paper, we introduce a generalization of derivations. Using these so-called secondary derivations, along with an analogue of Connes' Long Exact Sequence, we are able to provide computations in low dimension for the secondary…

Commutative Algebra · Mathematics 2023-02-24 Kylie Bennett , Elizabeth Heil , Jacob Laubacher

We prove that extension groups in strict polynomial functor categories compute the rational cohomology of classical algebraic groups. This result was previously known only for general linear groups. We give several applications to the study…

Representation Theory · Mathematics 2010-12-13 Antoine Touzé

In this work, we study the Hochschild-Mitchell Cohomology of triangular matrix categories. Given a triangular matrix category $\Lambda=\left[ \begin{smallmatrix} \mathcal{T} & 0 \\ M & \mathcal{U} \end{smallmatrix}\right]$, we investigate…

Representation Theory · Mathematics 2026-01-15 V. Santiago-Vargas , E. O. Velasco-Páez

We generalize and clarify Gerstenhaber and Schack's "Special Cohomology Comparison Theorem". More specifically we obtain a fully faithful functor between the derived categories of bimodules over a prestack over a small category U and the…

K-Theory and Homology · Mathematics 2009-05-15 Wendy Lowen , Michel Van den Bergh

We introduce Hochschild (co-)homology of morphisms of schemes or analytic spaces and study its fundamental properties. In analogy with the cotangent complex we introduce the so called (derived) Hochschild complex of a morphism; the…

Algebraic Geometry · Mathematics 2007-05-23 R. -O. Buchweitz , H. Flenner

Let $\k$ be a commutative ring, and let $(A,\mfrak{a})$ be an adic ring which is a $\k$-algebra. We study complete and torsion versions of the derived Hochschild homology and cohomology functors of $A$ over $\k$. To do this, we first…

Commutative Algebra · Mathematics 2013-08-28 Liran Shaul

The notion of a duality between two derived functors as well as an extension theorem for derived functors to larger categories in which they need not be defined is introduced. These ideas are then applied to extend and study the coext…

Rings and Algebras · Mathematics 2014-02-19 Anastasis Kratsios

This paper presents the structure conversion by which from an Ann-category $\A,$ we can obtain its reduced Ann-category of the type $(R,M)$ whose structure is a family of five functions $k=(\xi,\eta,\alpha,\lambda,\rho)$. Then we will show…

Category Theory · Mathematics 2013-09-17 Nguyen Tien Quang

We show that the ordinary cohomology functor from the category of augmented $k$-algebras to itself exchanges coproducts and products, and that Hochschild cohomology is close to sending coproducts to products if the factors are…

Representation Theory · Mathematics 2010-07-26 Matthew Towers

In this paper, we study the higher Hochschild functor and its relationship with factorization algebras and topological chiral homology. To this end, we emphasize that the higher Hochschild complex is a $(\infty,1)$-functor from the category…

Quantum Algebra · Mathematics 2012-06-01 Gregory Ginot , Thomas Tradler , Mahmoud Zeinalian

We show in this work that homology in degree d of a congruence group, in a very general framework, defines a weakly polynomial functor of degree at most 2d and we describe this functor modulo polynomial functors of smaller degree. Our main…

K-Theory and Homology · Mathematics 2017-12-12 Aurélien Djament

We propose a new look on triangulated categories, which is based on the second Hochschild cohomology.

K-Theory and Homology · Mathematics 2008-02-21 Teimuraz Pirashvili

We build an explicit link between coherent functors in the sense of Auslander and strict polynomial functors in the sense of Friedlander and Suslin. Applications to functor cohomology are discussed.

Representation Theory · Mathematics 2008-05-19 Vincent Franjou , Teimuraz Pirashvili

We initiate the study of the cohomology of (strict polynomial) bifunctors by introducing the foundational formalism, establishing numerous properties in analogy with the cohomology of functors, and providing computational techniques. Since…

K-Theory and Homology · Mathematics 2008-05-19 Vincent Franjou , Eric M. Friedlander

Given a mechanical system $(M, \mathcal{F}(M))$, where $M$ is a Poisson manifold and $\mathcal{F}(M)$ the algebra of regular functions on $M$, it is important to be able to quantize it, in order to obtain more precise results than through…

Mathematical Physics · Physics 2008-12-18 Frédéric Butin

We set up a fibred categorical theory of obstruction and classification of morphisms that specializes to the one of monoidal functors between categorical groups and also to the Schreier-Mac Lane theory of group extensions. Further…

Category Theory · Mathematics 2021-04-14 Alan S. Cigoli , Sandra Mantovani , Giuseppe Metere , Enrico M. Vitale

We prove standard results of group cohomology -- namely, existence of a long exact sequence, classification of torsors via the first cohomology group, Shapiro's lemma, the Hochschild-Serre spectral sequence, a decomposition of the cochain…

Group Theory · Mathematics 2022-03-15 Oliver Thomas

A relative derived category for the category of modules over a presheaf of algebras is constructed to identify the relative Yoneda and Hochschild cohomologies with its homomorphism groups. The properties of a functor between this category…

Category Theory · Mathematics 2014-04-16 Alin Stancu