--- a/src/HOL/Library/Ring_and_Field_Example.thy Fri Nov 21 11:15:40 2003 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,25 +0,0 @@
-
-header {* \title{}\subsection{Example: The ordered ring of integers} *}
-
-theory Ring_and_Field_Example = Main:
-
-text{*The Integers Form an Ordered Ring*}
-instance int :: ordered_ring
-proof
- fix i j k :: int
- show "(i + j) + k = i + (j + k)" by simp
- show "i + j = j + i" by simp
- show "0 + i = i" by simp
- show "- i + i = 0" by simp
- show "i - j = i + (-j)" by simp
- show "(i * j) * k = i * (j * k)" by simp
- show "i * j = j * i" by simp
- show "1 * i = i" by simp
- show "(i + j) * k = i * k + j * k" by (simp add: int_distrib)
- show "0 \<noteq> (1::int)" by simp
- show "i \<le> j ==> k + i \<le> k + j" by simp
- show "i < j ==> 0 < k ==> k * i < k * j" by (simp add: zmult_zless_mono2)
- show "\<bar>i\<bar> = (if i < 0 then -i else i)" by (simp only: zabs_def)
-qed
-
-end