From 4d05522c1b16775f402df6d2cf62b19e6fdcb8e9 Mon Sep 17 00:00:00 2001 From: Jan Hlavacek Date: Sat, 1 Jan 2022 22:08:55 -0500 Subject: [PATCH] Add missing s in proof of composition law In the proof of the functor composition law for Stack, the actual stack `s` disappears on the last two lines. --- README.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/README.md b/README.md index 117ea63..cbdb294 100644 --- a/README.md +++ b/README.md @@ -367,8 +367,8 @@ instance Functor Stack where -- \n -> (f . g) (⟦ s ⟧ n) = -- \n -> f (g (⟦ s ⟧ n)) = -- \n -> f ⟦ fmap g s ⟧ n = --- \n -> ⟦ fmap f (fmap g) ⟧ n = --- ⟦ fmap f . fmap g ⟧ +-- \n -> ⟦ fmap f ((fmap g) s) ⟧ n = +-- ⟦ (fmap f . fmap g) s ⟧ ``` We could just give a sensible definition for `fmap` first and then see if the laws would