# HG changeset patch # User wenzelm # Date 976137011 -3600 # Node ID 62a2f9d9316cfcc424c103774d3c8c9233cdf1f1 # Parent 3d15596ee644bac7064a122a8b055c5a767e2d3e unsymbolize; diff -r 3d15596ee644 -r 62a2f9d9316c src/HOL/Library/Ring_and_Field.thy --- a/src/HOL/Library/Ring_and_Field.thy Wed Dec 06 22:08:49 2000 +0100 +++ b/src/HOL/Library/Ring_and_Field.thy Wed Dec 06 22:10:11 2000 +0100 @@ -50,14 +50,14 @@ lemma right_zero [simp]: "a + 0 = (a::'a::ring)" proof - have "a + 0 = 0 + a" by (simp only: add_commute) - also have "\ = a" by simp + also have "... = a" by simp finally show ?thesis . qed lemma add_left_commute: "a + (b + c) = b + (a + (c::'a::ring))" proof - have "a + (b + c) = (a + b) + c" by (simp only: add_assoc) - also have "\ = (b + a) + c" by (simp only: add_commute) + also have "... = (b + a) + c" by (simp only: add_commute) finally show ?thesis by (simp only: add_assoc) qed @@ -66,7 +66,7 @@ lemma right_minus [simp]: "a + -(a::'a::ring) = 0" proof - have "a + -a = -a + a" by (simp add: ring_add_ac) - also have "\ = 0" by simp + also have "... = 0" by simp finally show ?thesis . qed @@ -86,23 +86,23 @@ subsubsection {* Derived rules for multiplication *} -lemma right_one [simp]: "a = a * (#1\'a::field)" +lemma right_one [simp]: "a = a * (#1::'a::field)" proof - have "a = #1 * a" by simp - also have "\ = a * #1" by (simp add: mult_commute) + also have "... = a * #1" by (simp add: mult_commute) finally show ?thesis . qed lemma mult_left_commute: "a * (b * c) = b * (a * (c::'a::ring))" proof - have "a * (b * c) = (a * b) * c" by (simp only: mult_assoc) - also have "\ = (b * a) * c" by (simp only: mult_commute) + also have "... = (b * a) * c" by (simp only: mult_commute) finally show ?thesis by (simp only: mult_assoc) qed theorems ring_mult_ac = mult_assoc mult_commute mult_left_commute -lemma right_inverse [simp]: "a \ 0 \ a * inverse (a::'a::field) = #1" +lemma right_inverse [simp]: "a \ 0 ==> a * inverse (a::'a::field) = #1" proof - have "a * inverse a = inverse a * a" by (simp add: ring_mult_ac) also assume "a \ 0" @@ -110,7 +110,7 @@ finally show ?thesis . qed -lemma right_inverse_eq: "b \ 0 \ (a / b = #1) = (a = (b::'a::field))" +lemma right_inverse_eq: "b \ 0 ==> (a / b = #1) = (a = (b::'a::field))" proof assume neq: "b \ 0" { @@ -123,7 +123,7 @@ } qed -lemma divide_self [simp]: "a \ 0 \ a / (a::'a::field) = #1" +lemma divide_self [simp]: "a \ 0 ==> a / (a::'a::field) = #1" by (simp add: divide_inverse) @@ -132,8 +132,8 @@ lemma right_distrib: "a * (b + c) = a * b + a * (c::'a::ring)" proof - have "a * (b + c) = (b + c) * a" by (simp add: ring_mult_ac) - also have "\ = b * a + c * a" by (simp only: left_distrib) - also have "\ = a * b + a * c" by (simp add: ring_mult_ac) + also have "... = b * a + c * a" by (simp only: left_distrib) + also have "... = a * b + a * c" by (simp add: ring_mult_ac) finally show ?thesis . qed