Mercurial > hg > Members > atton > similar_monad

comparison agda/list.agda @ 31:33b386de3f56

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Proof list-associative
author Yasutaka Higa <e115763@ie.u-ryukyu.ac.jp>
date Sat, 18 Oct 2014 13:38:29 +0900
parents 5ba82f107a95
children 743c05b98dad
comparison
equal deleted inserted replaced
30:c2f40b6d4027 31:33b386de3f56
23 empty-append (x :: xs) = begin 23 empty-append (x :: xs) = begin
24 x :: (xs ++ []) 24 x :: (xs ++ [])
25 ≡⟨ cong (_::_ x) (empty-append xs) ⟩ 25 ≡⟨ cong (_::_ x) (empty-append xs) ⟩
26 x :: xs 26 x :: xs
27 ∎ 27 ∎
28
29
30 list-associative : {A : Set} -> (a b c : List A) -> (a ++ (b ++ c)) ≡ ((a ++ b) ++ c)
31 list-associative [] b c = refl
32 list-associative (x :: a) b c = cong (_::_ x) (list-associative a b c)