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hmemcpy / milewski-ctfp-pdf

Bartosz Milewski's 'Category Theory for Programmers' unofficial PDF and LaTeX source
https://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/
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typo on notation of the horizontal composition #168

Closed 5d closed 5 years ago

5d commented 5 years ago

the notation of horizontal natural transformation compose should be dot ⋅, not circle ∘

BartoszMilewski commented 5 years ago

I'm following McLane here. He uses a circle. I realize that it could be confusing, but I don't want to argue with McLane.

5d commented 5 years ago

@BartoszMilewski , I thought the small circle means the dot, because in the following equation

(𝛽′ ⋅𝛼′)∘(𝛽 ⋅𝛼) = (𝛽′ ∘𝛽)⋅(𝛼′ ∘𝛼)

the horizontal compositions are using ⋅, and vertical one is ∘, I am new to category theory and functional programming, this book is really mind blowing, thanks a lot, happy new year!