Theorem "(x::int) dvd 1 = ( ¦x¦ = 1)" added to default simpset.
This solves the goals like "~ 4 dvd 1". This used to fail before.
--- a/src/HOL/Integ/IntDiv.thy Fri Jan 19 13:16:37 2007 +0100
+++ b/src/HOL/Integ/IntDiv.thy Fri Jan 19 15:13:47 2007 +0100
@@ -1243,7 +1243,7 @@
apply (simp add: mult_ac)
done
-lemma zdvd1_eq: "(x::int) dvd 1 = ( \<bar>x\<bar> = 1)"
+lemma zdvd1_eq[simp]: "(x::int) dvd 1 = ( \<bar>x\<bar> = 1)"
proof
assume d: "x dvd 1" hence "int (nat \<bar>x\<bar>) dvd int (nat 1)" by (simp add: zdvd_abs1)
hence "nat \<bar>x\<bar> dvd 1" by (simp add: zdvd_int)