Added global let-simplification rule.
(* Title: HOL/Numeral.ML
ID: $Id$
Author: Tobias Nipkow
*)
(*Unfold all "let"s involving constants*)
Goalw [Let_def] "Let (number_of v) f == f (number_of v)";
by(Simp_tac 1);
qed "Let_number_of";
Addsimps [Let_number_of];