shorten proof

9a04511b · Ralf Jung · c07a5eec · 9a04511b
Commit 9a04511b authored Jul 13, 2019 by Ralf Jung
--- a/theories/algebra/cmra.v
+++ b/theories/algebra/cmra.v
@@ -1144,8 +1144,7 @@ Section prod.
    core (a, b) = (core a, core b).
  Proof.
    rewrite /core /core' {1}/pcore /=.
-    rewrite (cmra_pcore_core a). simpl.
-    rewrite (cmra_pcore_core b). done.
+    rewrite (cmra_pcore_core a) /= (cmra_pcore_core b). done.
  Qed.

  Global Instance prod_cmra_total : CmraTotal A → CmraTotal B → CmraTotal prodR.