changeset 23969 | ef782bbf2d09 |
parent 23853 | 2c69bb1374b8 |
child 23983 | 79dc793bec43 |
--- a/src/HOL/IntDiv.thy Tue Jul 24 19:46:44 2007 +0200 +++ b/src/HOL/IntDiv.thy Tue Jul 24 19:58:53 2007 +0200 @@ -1231,6 +1231,11 @@ thus ?thesis by blast qed +lemma zdvd_zmult_cancel_disj[simp]: + "(k*m) dvd (k*n) = (k=0 | m dvd (n::int))" +by (auto simp: zdvd_zmult_mono dest: zdvd_mult_cancel) + + theorem ex_nat: "(\<exists>x::nat. P x) = (\<exists>x::int. 0 <= x \<and> P (nat x))" apply (simp split add: split_nat) apply (rule iffI)