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[helm.git] / helm / software / matita / library / nat / nat.ma

diff --git a/helm/software/matita/library/nat/nat.ma b/helm/software/matita/library/nat/nat.ma
index 9fce4df76a8b3dfbd7071582202ea648676d884b..b098279e62e9ed3ecf1cf99a04e564faaf3bbf2c 100644 (file)
--- a/helm/software/matita/library/nat/nat.ma
+++ b/helm/software/matita/library/nat/nat.ma
@@ -18,6 +18,9 @@ inductive nat : Set \def
   | O : nat
   | S : nat \to nat.
 
+interpretation "Natural numbers" 'N = nat.
+alias num (instance 0) = "natural number".
+
 definition pred: nat \to nat \def
  \lambda n:nat. match n with
  [ O \Rightarrow  O