# HG changeset patch
# User haftmann
# Date 1265728029 -3600
# Node ID 894e82be8d05ccb8b7390dfa0e967655c1610b7b
# Parent 698f0bfb560ea2e8f474d5bbce1a2b75e1568e99
simple proofs make life faster and easier
diff -r 698f0bfb560e -r 894e82be8d05 src/HOL/Real.thy
--- a/src/HOL/Real.thy Tue Feb 09 14:32:16 2010 +0100
+++ b/src/HOL/Real.thy Tue Feb 09 16:07:09 2010 +0100
@@ -9,21 +9,18 @@
proof (rule ccontr)
assume xy: "\ x \ y"
hence "(x-y)/2 > 0"
- by (metis half_gt_zero le_iff_diff_le_0 linorder_not_le local.xy)
+ by simp
hence "x \ y + (x - y) / 2"
by (rule e [of "(x-y)/2"])
also have "... = (x - y + 2*y)/2"
- by auto
- (metis add_less_cancel_left add_numeral_0_right class_semiring.add_c xy e
- diff_add_cancel gt_half_sum less_half_sum linorder_not_le number_of_Pls)
+ by (simp add: diff_divide_distrib)
also have "... = (x + y) / 2"
- by auto
+ by simp
also have "... < x" using xy
- by auto
+ by simp
finally have "x