Mercurial > hg > Papers > 2020 > soto-midterm

diff src/NatAddSym.agda @ 1:73127e0ab57c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
(none)
author soto@cr.ie.u-ryukyu.ac.jp
date Tue, 08 Sep 2020 18:38:08 +0900
parents
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/NatAddSym.agda	Tue Sep 08 18:38:08 2020 +0900
@@ -0,0 +1,12 @@
+open import Relation.Binary.PropositionalEquality
+open import nat
+open import nat_add
+open ≡-Reasoning
+
+module nat_add_sym where
+
+addSym : (n m : Nat) -> n + m ≡ m + n
+addSym O       O   = refl
+addSym O    (S m)  = cong S (addSym O m)
+addSym (S n)   O   = cong S (addSym n O) 
+addSym (S n) (S m) = {!!} -- 後述