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Search options not deleted user 13767
13 votes
1 answer
499 views

Is there something like "Noncommutative geometry internal to a category"?

I have heard that one can do algebraic geometry internal to symmetric monoidal categories. Topological quantum field theories also exist internal to symmetric monoidal categories, and the usual defini …
Manuel Bärenz's user avatar
5 votes
2 answers
1k views

When is the endofunctor category of a monoidal category braided? When is it ribbon? Fusion? ...

Given a category $\mathcal{C}$, we can define the category of endofunctors $\operatorname{Cat}(\mathcal{C})$, with objects functors $F: \mathcal{C} \to \mathcal{C}$ and morphisms natural transformatio …
Manuel Bärenz's user avatar
8 votes
0 answers
370 views

Is there a classification of 2d extended TQFTs with defects?

Chris Schommer-Pries has classified 2d extended TQFTs (topological quantum field theories) in his PhD thesis. The result is a (not necessarily abelian) separable symmetric Frobenius algebra (possibly …
Manuel Bärenz's user avatar
2 votes
1 answer
152 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 obje …
Manuel Bärenz's user avatar
10 votes
2 answers
598 views

What are TQFTs that are multiplicative under connected sums? Do bordisms with connected sum ...

In general, one extracts a manifold invariant from a TQFT by interpreting the closed manifold as a bordism from the empty set to the empty set. The TQFT sends this bordism to a homomorphism of the gro …
Manuel Bärenz's user avatar
6 votes
1 answer
337 views

Is there a quotient or exact sequence of symmetric, premodular (ribbon fusion) and modular c...

In Walker and Wang's article about (3+1)-TQFTs from premodular categories, they say on page 14 that you can take a quotient of a premodular category $\mathcal{C}$ by its symmetric fusion subcategory …
Manuel Bärenz's user avatar