It's 5am and I keep having to draw pairs of pants because I have to give a talk tmrw.
Real ones will understand
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It's 5am and I keep having to draw pairs of pants because I have to give a talk tmrw.
Real ones will understand
Tumblr would be way cooler if it had more posts on topological field theory damn i thought people came here to rant about their special interests
(via https://www.youtube.com/watch?v=IeXsUVIfot4)
soundtrack music anyone?
pants
copants
cobordisms
tensors
braids
topological quantum field theory
presented by Kevin Lin
from Joachim Kock's book
Frobenius algebras and 2D topological quantum field theories
whose dedication page simply reads "For fun"
他にもこのサイトにはとても参考になる``噂ばなし''が載っている.
「site:http://pantodon.shinshu-u.ac.jp/」 とのand検索 でいろいろ検索するとためになるだろう.
Graphical Axioms from the nCatLab
If you don't read the n-category café's wiki project, you are missing out.
Definition. A Frobenius algebra in a monoidal category is a quadruple (A,δ,ϵ,μ,η) such that
(A,μ,η) is a monoid,
(A,δ,ϵ) is a comonoid, and
the Frobenius laws hold: (1⊗μ)∘(δ⊗1)=δ∘μ=(μ⊗1)∘(1⊗δ).
In terms of string diagrams, this definition says:
The first line here shows the associative law and left/right unit laws for a monoid. The second line shows the coassociative law and left/right counit laws for a comonoid. The third line shows the Frobenius laws.
...
Certain kinds of Frobenius algebras have nice PROPs or PROs. The PRO for Frobenius algebras is the monoidal category of planar thick tangles, as noted by Aaron Lauda Lauda (2006) and illustrated here:
Lauda and Pfeiffer Lauda (2008) showed that the PROP for symmetric Frobenius algebras is the category of ‘topological open strings’, since it obeys this extra axiom:
... [A]ny commutative Frobenius algebra gives a 2d TQFT.... The monoid laws look like this:
The comonoid laws look like this:
The Frobenius laws look like this:
and the commutative law looks like this:
...
A special commutative Frobenius algebra gives a 2d TQFT that is insensitive to the genus of a 2-manifold, since in terms of pictures, the ‘specialness’ axioms ∘δ=1 says that