--- a/src/HOL/Old_Number_Theory/Legacy_GCD.thy Sat Oct 17 01:05:59 2009 +0200
+++ b/src/HOL/Old_Number_Theory/Legacy_GCD.thy Sat Oct 17 14:43:18 2009 +0200
@@ -1,4 +1,4 @@
-(* Title: HOL/GCD.thy
+(* Title: HOL/Old_Number_Theory/Legacy_GCD.thy
Author: Christophe Tabacznyj and Lawrence C Paulson
Copyright 1996 University of Cambridge
*)
@@ -331,31 +331,31 @@
moreover
{assume db: "d=b"
from prems have ?thesis apply simp
- apply (rule exI[where x = b], simp)
- apply (rule exI[where x = b])
- by (rule exI[where x = "a - 1"], simp add: diff_mult_distrib2)}
+ apply (rule exI[where x = b], simp)
+ apply (rule exI[where x = b])
+ by (rule exI[where x = "a - 1"], simp add: diff_mult_distrib2)}
moreover
{assume db: "d < b"
- {assume "x=0" hence ?thesis using prems by simp }
- moreover
- {assume x0: "x \<noteq> 0" hence xp: "x > 0" by simp
-
- from db have "d \<le> b - 1" by simp
- hence "d*b \<le> b*(b - 1)" by simp
- with xp mult_mono[of "1" "x" "d*b" "b*(b - 1)"]
- have dble: "d*b \<le> x*b*(b - 1)" using bp by simp
- from H (3) have "a * ((b - 1) * y) + d * (b - 1 + 1) = d + x*b*(b - 1)" by algebra
- hence "a * ((b - 1) * y) = d + x*b*(b - 1) - d*b" using bp by simp
- hence "a * ((b - 1) * y) = d + (x*b*(b - 1) - d*b)"
- by (simp only: diff_add_assoc[OF dble, of d, symmetric])
- hence "a * ((b - 1) * y) = b*(x*(b - 1) - d) + d"
- by (simp only: diff_mult_distrib2 add_commute mult_ac)
- hence ?thesis using H(1,2)
- apply -
- apply (rule exI[where x=d], simp)
- apply (rule exI[where x="(b - 1) * y"])
- by (rule exI[where x="x*(b - 1) - d"], simp)}
- ultimately have ?thesis by blast}
+ {assume "x=0" hence ?thesis using prems by simp }
+ moreover
+ {assume x0: "x \<noteq> 0" hence xp: "x > 0" by simp
+
+ from db have "d \<le> b - 1" by simp
+ hence "d*b \<le> b*(b - 1)" by simp
+ with xp mult_mono[of "1" "x" "d*b" "b*(b - 1)"]
+ have dble: "d*b \<le> x*b*(b - 1)" using bp by simp
+ from H (3) have "a * ((b - 1) * y) + d * (b - 1 + 1) = d + x*b*(b - 1)" by algebra
+ hence "a * ((b - 1) * y) = d + x*b*(b - 1) - d*b" using bp by simp
+ hence "a * ((b - 1) * y) = d + (x*b*(b - 1) - d*b)"
+ by (simp only: diff_add_assoc[OF dble, of d, symmetric])
+ hence "a * ((b - 1) * y) = b*(x*(b - 1) - d) + d"
+ by (simp only: diff_mult_distrib2 add_commute mult_ac)
+ hence ?thesis using H(1,2)
+ apply -
+ apply (rule exI[where x=d], simp)
+ apply (rule exI[where x="(b - 1) * y"])
+ by (rule exI[where x="x*(b - 1) - d"], simp)}
+ ultimately have ?thesis by blast}
ultimately have ?thesis by blast}
ultimately have ?thesis by blast}
ultimately show ?thesis by blast