414 reputation
211
bio website
location
age
visits member for 3 years, 7 months
seen 12 hours ago

13h
comment Defining the category of groups and center-preserving homomorphisms by a universal property; does this actually work?
Your twisted cone is actually a morphism of spans. I don't know whether your construction works, but there is plenty of theory about spans.
13h
answered Algebraic process to find numbers so that $xy=45$ and $x+y=18$
13h
comment Reference for understanding coalgebra
Majid's book "Foundations of quantum group theory" comes with an introduction to coalgebras and bialgebras. It's not very hard on the category theory.
13h
comment Algebraic process to find numbers so that $xy=45$ and $x+y=18$
You need the pq-formula.
Jul
30
comment Why do we still do symbolic math?
One could go so far and say that there is no such thing as a "numerical solution", only a numerical approximation.
Jul
24
accepted Why are duals in a rigid/autonomous category unique up to unique isomorphism?
Jul
23
answered Why are duals in a rigid/autonomous category unique up to unique isomorphism?
Jul
22
awarded  Yearling
Jul
22
awarded  Excavator
Jul
22
comment Why are duals in a rigid/autonomous category unique up to unique isomorphism?
@ZhenLin, great, thanks! Do you want to make this into an answer? (If you don't have the time I can do that as well)
Jul
22
comment Why are duals in a rigid/autonomous category unique up to unique isomorphism?
Oh, maybe I understand what you're getting at: While $Y$ and $Y$ are the same objects, $(Y,\epsilon,\eta)$ and $(Y,e,h)$ are different duals. So the whole dual data is unique, but not the underlying object?
Jul
22
comment Why are duals in a rigid/autonomous category unique up to unique isomorphism?
@ZhenLin, what does "compatible with all that data" mean, other than "define the new $\epsilon$ and $\eta$ by composition" and "the new dual satisfies the snake identities"? As I see it now, my $(Y, e, h)$ is another dual and $f$ is a unique iso compatible with the data.
Jul
22
revised A coherence question in rigid monoidal categories
Clarified spelling and grammar
Jul
22
comment Why are duals in a rigid/autonomous category unique up to unique isomorphism?
@ZhenLin, yes, that's why I prove the snake identities for the new dualities. Or is there any more structure that the new duality must be compatible with?
Jul
22
comment A coherence question in rigid monoidal categories
Are you implicitly assuming a particular isomorphism $\hat{\hat Y} \cong Y$? So maybe you're actually considering a pivotal category? It's nonstandard to define a rigid category as a monoidal symmetrical closed category with duals. Usually, only the monoidal structure is needed to define duals.
Jul
22
suggested suggested edit on A coherence question in rigid monoidal categories
Jul
22
asked Why are duals in a rigid/autonomous category unique up to unique isomorphism?
Jul
8
answered $[0, 1)$ and $S^1$ not homeomorphic?
Jul
2
awarded  Curious
Apr
21
comment Underlying functor of tensor product in a closed and symmetric monoidal category.
I wonder how many people have actually read this question completely. Can you shorten it somehow? (If necessary, restrict the audience to more experienced people by shortening)