X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fdama_didactic%2Fex_deriv.ma;h=b451a0acce5dbf0eb92008cb2f4687cc20fad5d1;hb=b89690596acb0b24f1fd45da28ac04b4ad217e98;hp=59e881592b370d7c484810b33c17b75a1ded9c19;hpb=87bfe7fa6c7b906646a0094180e69c0b0373ce10;p=helm.git

diff --git a/helm/software/matita/dama_didactic/ex_deriv.ma b/helm/software/matita/dama_didactic/ex_deriv.ma
index 59e881592..b451a0acc 100644
--- a/helm/software/matita/dama_didactic/ex_deriv.ma
+++ b/helm/software/matita/dama_didactic/ex_deriv.ma
@@ -183,8 +183,6 @@ theorem dispari_in_pari: ∀ f:F. fdispari f → fpari f '.
  done.
 qed.
 
-axiom tech1: ∀n,m. F_OF_nat n + F_OF_nat m = F_OF_nat (n + m).
-
 alias symbol "plus" = "natural plus".
 alias num (instance 0) = "natural number".
 theorem de_prodotto_funzioni: