PS

Maybe monads in String diagrams

圏論 定義 Monad Haskell Enriched

Universality of coproducts

f:id:mbps:20151019033536p:plain

Merge morphism

  • \Delta : A + A \to A
  • \Delta := \lbrack 1 _ A, 1 _ A \rbrack

Initializing morphism

(とはたぶん言わない)

  • \operatorname{!} : 0 \to A

Monoidal category with finite coproducts

  • (\mathcal{Hask}, \mathtt{Either}, \mathtt{Void}) \sim (\mathcal{Set}, +, \emptyset)

Cocartesian monoidal category ともいう。

命題

f:id:mbps:20151023075010p:plain

Maybe monad

f:id:mbps:20151023151328p:plain

参考文献