From 1fd075440f3f9a671412a7d8d968990094bf783b Mon Sep 17 00:00:00 2001
From: wadler <wadler@inf.ed.ac.uk>
Date: Fri, 10 Jan 2020 11:02:28 -0300
Subject: [PATCH] fixed error in Lists
---
src/plfa/part1/Lists.lagda.md | 23 -----------------------
1 file changed, 23 deletions(-)
diff --git a/src/plfa/part1/Lists.lagda.md b/src/plfa/part1/Lists.lagda.md
index 8bfe4223..18e816ed 100644
--- a/src/plfa/part1/Lists.lagda.md
+++ b/src/plfa/part1/Lists.lagda.md
@@ -354,29 +354,6 @@ reverse of the second appended to the reverse of the first:
reverse (xs ++ ys) ≡ reverse ys ++ reverse xs
-```
-reverse-++-distrib : ∀ xs ys → reverse (xs ++ ys) ≡ reverse ys ++ reverse xs
-reverse-++-distrib [] ys =
- begin
- reverse ([] ++ ys)
- ≡⟨⟩
- reverse ys
- ≡⟨ sym (++-identityʳ (reverse ys)) ⟩
- reverse ys ++ reverse []
- ∎
-reverse-++-distrib (x ∷ xs) ys =
- begin
- reverse ((x ∷ xs) ++ ys)
- ≡⟨⟩
- reverse (xs ++ ys) ++ [ x ]
- ≡⟨ cong (_++ [ x ]) (reverse-++-distrib xs ys) ⟩
- (reverse ys ++ reverse xs) ++ [ x ]
- ≡⟨ ++-assoc (reverse ys) (reverse xs) [ x ] ⟩
- reverse ys ++ (reverse xs ++ [ x ])
- ∎
-```
-
-
#### Exercise `reverse-involutive` (recommended)
A function is an _involution_ if when applied twice it acts