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Questions tagged [symmetric-monoidal-categories]

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Properties of semisimple monoidal category

In my work, I have constructed a semisimple category which has two monoidal structures: the usual direct sum; and a new "tensor product". This "tensor product" have several nice ...
Nanoputian's user avatar
8 votes
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Symmetric monoidal structures on the functor taking presheaves

Let $\mathrm{Cat}_\infty$ be the $\infty$-category of small $\infty$-categories, $\mathrm{Pr}^\mathrm{L}$ be the $\infty$-category of presentable $\infty$-categories, and $\mathcal P(\mathcal C)$ be ...
W. Rether's user avatar
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"Closed $\mathscr{V}$-modules are uniquely (co)tensored $\mathscr{V}$-categories": shouldn't we assume they are also "mixed monoidal"?

$\newcommand{\M}{\mathcal{M}}\newcommand{\V}{\mathscr{V}}\newcommand{\hom}{\mathsf{hom}}$Throughout this post, $\V$ refers to some "cosmos", where I borrow the word "cosmos" from ...
FShrike's user avatar
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When a monoidal closed category is cartesian closed

Let $C$ be a monoidal closed category with tensor $\otimes$ and internal hom $[-, -]$. Suppose that $C$ acts by adjoint monads, i.e. $- \otimes X$ is a comonad and $[X, -]$ is a monad, and each $F : ...
Cayley-Hamilton's user avatar
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$\ast$-autonomous categories with non-invertible dualizing object?

1. Definition Firstly, recall the following nLab-definition of a $\ast$-autonomous category: A $\ast$-autonomous category is a symmetric closed monoidal category $(C,\otimes,I,\multimap)$ with a ...
M.C.'s user avatar
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2 answers
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Reference for free symmetric monoidal categories with duals on symmetric monoidal categories

The inclusion $U$ of the (2,1)-category of symmetric monoidal categories with duals into the (2,1)-category of symmetric monoidal categories admits a left 2-adjoint functor $L$ for formal reasons. In ...
Dmitri Pavlov's user avatar
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Tannaka without Yoneda?

I am studying enriched categories, and as I wrote in my previous question How is the morphism of composition in the enriched category of modules constructed?, this is very difficult because there are ...
Sergei Akbarov's user avatar
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How is the morphism of composition in the enriched category of modules constructed?

I asked this a week ago at MSE, but without success. I am studying enriched categories and I have a feeling that I am doing something wrong because all the way each step, each elementary proposition, ...
Sergei Akbarov's user avatar
2 votes
0 answers
136 views

Taking the homology of a chain complex, seen as a symmetric monoidal functor

I've found, in quite some places online (e.g. it's the last example in the wikipedia page about monoidal functors), a statement similar to this: Homology can be seen as a symmetric, monoidal functor $...
LorenzoPerticone's user avatar
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1 answer
242 views

Day convolution for bimonoidal categories

Semiring categories, also called rig categories or bimonoidal categories, are pseudomonoids in the symmetric monoidal bicategory $(\mathsf{SymMonCats},\otimes_{\mathbb{F}},\mathbb{F})$¹. These are a ...
Emily's user avatar
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Symmetric monoidal structure on categorical nerves

There are several notions of nerves, including nerves of categories, $2$-categories, and simplicial categories. These define functors \begin{align*} \mathrm{N} &\colon \mathrm{Cats}_{(2,1)} ...
Emily's user avatar
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What is an invertible operad?

Let $\mathcal V$ be a nice symmetric monoidal ($\infty$-)category, and consider the ($\infty$-)category $Op(\mathcal V)$ of $\mathcal V$-enriched (symmetric) operads, symmetric monoidal under the ...
Tim Campion's user avatar
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1 answer
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Functors that preserve monoids

In the comments section of this question there was a question that I don't know if it has been asked on the site. It is well-known and easily proved that lax monoidal functors preserve monoids. So the ...
Javi's user avatar
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Functors between module categories that comes from restriction

Suppose you have two $k$ algebras $A, B$ (say also finitely generated if this helps) and a functor $F: A-mod \to B-mod $ such that $| F(M) |= |M|$. Here $|U|$ denotes the underlying $k$ vector space. ...
Andrea Marino's user avatar
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1 answer
431 views

Braided monoidal category, example

Let $H$ be a cocommutative hopf algebra. Let $M$ be the category of $H$-bimodules. Does the category $M$ form a braided monoidal category with tensor product $\otimes_{H}$ ?
lun's user avatar
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Is every $\otimes$-invertible object "coherently sym-central"?

Let $\mathcal C$ be a symmetric monoidal $\infty$-category, and let $L \in \mathcal C$ be a $\otimes$-invertible object. Then the braiding $L \otimes L \to L \otimes L$ is simply multiplication by $\...
Tim Campion's user avatar
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Symmetric monoidal structure(s) on the $\infty$-category of dg-categories

Let $k$ be a commutative ring with $1$, and let $\mathsf{dgCat}_k$ be the category of $k$-linear dg-categories, as defined in [1, Section 2]. We may equip $\mathsf{dgCat}_k$ with the Morita model ...
Stahl's user avatar
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3 votes
1 answer
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Frobenius algebras and traces of modules

$\newcommand{\Hom}{\mathscr{Hom}}$ Let $C$ be a cocomplete closed symmetric monoidal category, and the tensor product preserves colimits in each variable; Let $A$ be a commutative algebra in $C$, ...
Maxime Ramzi's user avatar
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6 votes
1 answer
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Formal completion of a quotient stack

$\newcommand{\Rep}{\operatorname{Rep}}$ $\newcommand{\mo}{\operatorname{-mod}}$ $\renewcommand{\hat}{\widehat}$ I apologize in advance if this is a naive question but my background in algebraic ...
Adrien's user avatar
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7 votes
2 answers
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References about "monoidal fibrations" in $\infty$-category theory

$\newcommand{\cat}{\mathsf} \newcommand{\fun}{\mathrm{Fun}} \newcommand{\calg}{\mathrm{CAlg}}$ Let $\cat C^\otimes,\cat D^\otimes, \cat E^\otimes$ be symmetric monoidal $\infty$-categories, and $p^\...
Maxime Ramzi's user avatar
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6 votes
1 answer
138 views

Tensor product of unit and co-unit in a closed compact category

Consider a compact closed category, i.e., a symmetric monoidal category with a unit $\eta$ and co-unit $\epsilon$. It seems natural to demand that the tensor product of two units (for different ...
Andi Bauer's user avatar
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R-matrices and symmetric fusion categories

Given a $\mathbb{C}$-linear braided fusion category $\mathcal{C}$ containing a fusion rule of the form e.g. \begin{equation}X\otimes Y\cong A\oplus B \oplus C\end{equation} (where $A,B, C, X$ and $Y$ ...
Meths's user avatar
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1 answer
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Automated rewriting of string diagrams in symmetric monoidal categories

Many algebraic structures, such as Frobenius algebras, or quasi-triangular Hopf algebras, can be formulated in an arbitrary symmetric monoidal category. They are given by a collection of morphisms, ...
Andi Bauer's user avatar
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1 vote
0 answers
254 views

Oplax monoidal functors of $\infty$-categories

In Higher Algebra, a notion of lax symmetric monoidal functors (in what follows, I'll remove the adjective "symmetric", but I'm mainly interested in the symmetric situation) is defined : if you have ...
Maxime Ramzi's user avatar
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Does Cantor Bernstein hold in a Closed Symmetric Monoidal Category?

In a closed symmetric monoidal category with $[I,X] \cong X$ for all $X$ is it true that having monomorphisms $m :A \rightarrow B$ and $m: B \rightarrow A$ is enough to imply $A \cong B$ ? I tried to ...
Cat_W's user avatar
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Very basic question about category theory

I have a symmetric monoidal category, and go to another one by replacing objects with isomorphism classes of objects. What's that called in category theory language? To give an example, consider the ...
Andi Bauer's user avatar
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3 votes
2 answers
302 views

The symmetric monoidal closed structure on the category of $\mathcal{F}$-cocomplete categories and $\mathcal{F}$-cocontinuous functors

In 6.5 of the book by Kelly, Basic concepts of enriched category theory. Reprints in Theory and Applications of Categories, No. 10, 2005. the author claims that the $2$-category $\mathsf{Cat}_{\...
Ivan Di Liberti's user avatar
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2 answers
705 views

Mac Lane's proof of coherence for symmetric monoidal categories

This question only concerns the final part of the proof, so I assume that the symmetric monoidal category is a strict monoidal category $\mathsf{C}$ with the braiding $s$. Let $X_1,...,X_n$ be ...
Jxt921's user avatar
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2 votes
0 answers
200 views

Deligne's internal characterisation of Tannakian categories - glueing of algebras

I am currently reading the proof of Deligne's internal characterization of Tannakian categories (Thm. 7.1) in Deligne: Catégories tannakiennes. My question is similar to this one. Given a ...
Aaron Wild's user avatar
9 votes
2 answers
470 views

A question about the Tannaka-Krein reconstruction of finite groups

In Chapter 15 Section 15.2.1 of Quantum Groups and Noncommutative Geometry, 2nd edition, the authors raised a question: can we reconstruct a finite group $G$ from its category of finite dimensional ...
Zhaoting Wei's user avatar
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4 votes
1 answer
415 views

Krein's theorem in the Tannaka-Krein duality

In the Tannaka-Krein duality theory, the Krein theorem describes the conditions under which a given category $\varPi$ is a category of finite-dimensional representations of some compact group $G$: ...
Sergei Akbarov's user avatar
6 votes
0 answers
413 views

"Fundamental theorem for Hopf modules"

I am studying Hopf algebras in categories, and I hope, somebody could help me with the following. Joost Vercruysse in his paper Hopf algebras---Variant notions and reconstruction theorems writes (...
Sergei Akbarov's user avatar
6 votes
2 answers
338 views

Symmetric monoidal category with trivial switch morphisms

Is there a specific terminology for a symmetric monoidal category in which for any object $x$ the switch map $x\otimes x\to x\otimes x$ is the identity ? (Or alternatively the action of the symmetric ...
Captain Lama's user avatar
5 votes
1 answer
316 views

Tannaka duality for closed monoidal categories

I asked this some time ago at mathstackexchange, and people there explained to me the mathematical part of what I was asking, but the question about references remains open. In my impression, people ...
Sergei Akbarov's user avatar
10 votes
1 answer
425 views

Trace in the category of propositional statements

By the result in this paper, there exists a categorification of the trace of a linear operator that generalizes to any endomorphism of a dualizable object in a symmetric monoidal category ($\textbf{...
failedentertainment's user avatar
3 votes
0 answers
138 views

Can the effective topos be seen as symmetric monoidal?

In Example(s) of monoidal symmetric closed category with NNO without infinite coproducts? user Zhen Lin states the effective topos is locally cartesian closed. On nLab we have that locally ...
DV196883's user avatar
6 votes
0 answers
119 views

Computing weak operadic colimits as colimits

I am trying to reduce the computation of weak operadic colimits to colimits. Let me introduct some notation. Let $q:C^{\otimes} \to N(Fin_*)$ be a symmetric monoidal category. Let $p: K \to C^{\...
Andrea Marino's user avatar
3 votes
1 answer
281 views

Symmetric monoidal structure on algebras

I stuck at a relatively simple thing of formalization in infinity setting. I use here the formalism of quasi categories, i.e. simplicial sets with inner horn fillings. Suppose $O^{\otimes}$ is an ...
Andrea Marino's user avatar
11 votes
3 answers
381 views

Inequivalent compact closed symmetric monoidal structures on the same category

I am looking for interesting examples of categories admitting multiple monoidally inequivalent closed (or compact closed) symmetric monoidal structures. We know how to construct disconnected toy ...
Stefano Gogioso's user avatar
10 votes
1 answer
282 views

Is every symmetric monoidal combinatorial model category symmetric monoidally Quillen equivalent to a simplicial such?

Is every symmetric monoidal combinatorial model category symmetric monoidally Quillen equivalent (by a zig-zag of symmetric monoidal Quillen equivalences) to a symmetric monoidal combinatorial ...
Hadrian Heine's user avatar
14 votes
2 answers
631 views

Status of Thomason's idea for a symmetric monoidal model of stable homotopy - from his last paper

In 1995, Robert Thomason published “Symmetric monoidal categories model all connective spectra” in TAC. On page 2, he argues that symmetric monoidal categories are more convenient than “May’s ...
David White's user avatar
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5 votes
0 answers
360 views

Derived tensor products and Tor of commutative monoids

Two commutative monoids $M,N$ have a tensor product $M\otimes N$ satisfying the universal property that there is a tensor-Hom adjunction for any other commutative monoid $L$: $$\text{Hom}(M\otimes N,L)...
John Berman's user avatar
20 votes
5 answers
888 views

If a $\otimes$-idempotent object has a dual, must it be self-dual?

Let $C$ be a symmetric monoidal category. Recall that a dual for $X \in C$ is an object $X^\vee$ and maps $\eta: I \to X \otimes X^\vee$ and $\varepsilon: X^\vee \otimes X \to I$ (where $I$ is the ...
Tim Campion's user avatar
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8 votes
1 answer
872 views

Monoidal tensor product which preserves directed limits

Given a symmetric monoidal category $Q$, is there a construction of a (preferably full and faithful strong) monoidal embedding of $Q$ into some symmetric monoidal closed category $M$ which has all ...
Bert Lindenhovius's user avatar
15 votes
1 answer
502 views

What are the advantages of various "models" for the motivic stable homotopy category

People use several distinct models for the motivic stable homotopy category (so, there are some choices for the underlying category and a collection of available model structures). I would like to ask ...
Mikhail Bondarko's user avatar
16 votes
0 answers
358 views

Representation categories and homology

Let $G$ be a finite group. Let $\mathcal{C}=Rep-G$ be the rigid $\mathbb{C}$-linear symmetric monoidal category of finite dimensional complex representations of $G$. Can we recover some homological ...
Ehud Meir's user avatar
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2 votes
0 answers
266 views

Free commutative monoid monad

Has the monad induced by the free commutative monoid functor already been studied anywhere? Does it have any particular properties (other than not being cartesian)? I would prefer a reference on ...
geodude's user avatar
  • 2,057
4 votes
1 answer
240 views

Left adjoint for categories of commutative monoids?

The $n$Lab writes (prop. 2.2 in https://ncatlab.org/nlab/show/category+of+monoids) : Let $C$ be a monoidal category with countable coproducts that are preserved by the tensor product. Then the ...
user84563's user avatar
  • 905
2 votes
1 answer
133 views

How nontrivial can "central extensions of ribbon fusion categories" be?

In a sense, this is a follow up on this question, but one PhD programme later. Let $\mathcal{C}$ be ribbon fusion. By $\mathcal{C}'$, we denote the symmetric centre, i.e. the full subcategory of ...
Manuel Bärenz's user avatar
8 votes
1 answer
170 views

Temporal semantics for string diagrams

Suppose I have a string diagram $D$ which involves a set of strings $S$ and atomic processes $A$. Formally, we should think of this as a canonically chosen map in the free symmetric monoidal category (...
pnips's user avatar
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