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Related papers: Comodules, contramodules and Pontryagin duality

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We apply the super duality formalism recently developed by the authors to obtain new equivalences of various module categories of general linear Lie superalgebras. We establish the correspondence of standard, tilting, and simple modules, as…

Representation Theory · Mathematics 2012-12-19 Shun-Jen Cheng , Ngau Lam , Weiqiang Wang

We show that various cyclic and cocyclic modules attached to Hopf algebras and Hopf modules are related to each other via Connes' duality isomorphism for the cyclic category.

K-Theory and Homology · Mathematics 2007-05-23 M. Khalkhali , B. Rangipour

In Rev. Math. Phys. 4 (1997) 785 we study Hilbert-C* systems {F,G} where the fixed point algebra A has nontrivial center Z and where A'\cap F=Z is satisfied. The corresponding category of all canonical endomorphisms of A contains…

Operator Algebras · Mathematics 2007-05-23 Hellmut Baumgaertel , Fernando Lledo

There are at least three imprimitivity bimodules naturally associated to a maximal coaction of a discrete group G on a C*-algebra and a normal subgroup of G: Mansfield's bimodule; the bimodule assembled by Ng from Green's imprimitivity…

Operator Algebras · Mathematics 2007-05-23 S. Kaliszewski , John Quigg

Let $G$ be a compact connected Lie group and $K$ a closed connected subgroup. Assume that the order of any torsion element in the integral cohomology of $G$ and $K$ is invertible in a given principal ideal domain $k$. It is known that in…

Algebraic Topology · Mathematics 2021-11-24 Matthias Franz

We present applications of contramodule techniques to the Enochs conjecture about covers and direct limits, both in the categorical tilting context and beyond. In the $n$-tilting-cotilting correspondence situation, if $\mathsf A$ is a…

Category Theory · Mathematics 2021-09-15 Silvana Bazzoni , Leonid Positselski

For each finite semisimple tensor category, we associate a quantum group (face algebra) whose comodule category is equivalent to the original one, in a simple natural manner. To do this, we also give a generalization of the Tannaka-Krein…

Quantum Algebra · Mathematics 2007-05-23 Takahiro Hayashi

The paper presents a detailed description of duality for braided algebras, coalgebras, bialgebras, Hopf algebras and their modules and comodules in the infinite setting. Assuming that the dual objects exist, it is shown how a given braiding…

Quantum Algebra · Mathematics 2020-08-25 Elmar Wagner

We extend a construction of Hinich to obtain a closed model category structure on all differential graded cocommutative coalgebras over an algebraically closed field of characteristic zero. We further show that the Koszul duality between…

Algebraic Topology · Mathematics 2023-12-22 J. Chuang , A. Lazarev , Wajid Mannan

For coalgebras $C$ and $D$, Takeuchi proved that the category of linear functors from $\mathfrak{M}^C$ to $\mathfrak{M}^D$ preserving small coproducts is equivalent to the category of $C$-$D$-bicomodules, where $\mathfrak{M}^C$ for a…

Quantum Algebra · Mathematics 2025-10-10 Taiki Shibata , Kenichi Shimizu

If G is a finite group, some aspects of the modular representation theory depend on the cochains C^*(BG; k), viewed as a commutative ring spectrum. We consider its singularity category (in the sense of the author and Stevenson arxiv…

Algebraic Topology · Mathematics 2026-04-29 J. P. C. Greenlees

For any CDG-ring $B^\bullet=(B^*,d,h)$, we show that the homotopy category of graded-projective (left) CDG-modules over $B^\bullet$ is equivalent to the quotient category of the homotopy category of graded-flat CDG-modules by its full…

Rings and Algebras · Mathematics 2025-10-03 Leonid Positselski , Jan Stovicek

The aim of this paper is to explain how to get a complex of smooth representations out of the dual vector space to a smooth representation of a p-adic Lie group, in natural characteristic. The construction does not depend on any…

Category Theory · Mathematics 2020-02-20 Leonid Positselski

We show that the positive zoom complexes, with fairly natural morphisms, form a dual category to the category of positive opetopes with contraction epimorphisms. We also show how this duality can be extended to opetopic cardinals.

Category Theory · Mathematics 2023-04-18 Marek Zawadowski

The "linear dual" of a cocomplete linear category $\mathcal C$ is the category of all cocontinuous linear functors $\mathcal C \to \mathrm{Vect}$. We study the questions of when a cocomplete linear category is reflexive (equivalent to its…

Category Theory · Mathematics 2020-01-31 Martin Brandenburg , Alexandru Chirvasitu , Theo Johnson-Freyd

For a bialgebra $L$ coacting on a $\Bbbk$-algebra $A$, a classical result states that $A$ is a right $L$-comodule algebra if and only if $A$ is an algebra in the monoidal category $\mathcal{M}^{L}$ of right $L$-comodules; the former notion…

Quantum Algebra · Mathematics 2022-10-04 Chelsea Walton , Elizabeth Wicks , Robert Won

In this paper, we establish the global analogues of some dualities and equivalences in local algebra by developing the theory of relative Cohen-Macaulay modules. Let R be a commutative Noetherian ring (not necessarily local) with identity…

Commutative Algebra · Mathematics 2023-08-22 Parisa Pourghobadian , Kamran Divaani-Aazar , Ahad Rahimi

Contraherent cosheaves are module objects over algebraic varieties defined by gluing using the colocalization functors. Contraherent cosheaves are designed to be used for globalizing contramodules and contraderived categories for the…

Algebraic Geometry · Mathematics 2024-04-10 Leonid Positselski

For any compact $p$-adic Lie group $G$, the Iwasawa algebra $\Omega_G$ over finite field $\mathbb{F}_p$ is a complete noetherian semilocal algebra. It is shown that $\Omega_G$ is the dual algebra of an artinian coalgebra $C$. We induce a…

Rings and Algebras · Mathematics 2016-10-26 Zheng Fang , Feng Wei

Let $g$ be a reductive Lie algebra over a field of characteristic zero. Suppose $g$ acts on a complex of vector spaces $M$ by $i_\lambda$ and $L_\lambda$, which satisfy the identities as contraction and Lie derivative do for smooth…

Algebraic Geometry · Mathematics 2007-05-23 Tomasz Maszczyk , Andrzej Weber