--- a/src/HOL/Isar_examples/Peirce.thy Wed Jun 13 16:43:02 2007 +0200
+++ b/src/HOL/Isar_examples/Peirce.thy Wed Jun 13 18:30:11 2007 +0200
@@ -21,16 +21,16 @@
theorem "((A --> B) --> A) --> A"
proof
- assume aba: "(A --> B) --> A"
+ assume "(A --> B) --> A"
show A
proof (rule classical)
assume "~ A"
have "A --> B"
proof
assume A
- thus B by contradiction
+ with `~ A` show B by contradiction
qed
- with aba show A ..
+ with `(A --> B) --> A` show A ..
qed
qed
@@ -52,17 +52,17 @@
theorem "((A --> B) --> A) --> A"
proof
- assume aba: "(A --> B) --> A"
+ assume "(A --> B) --> A"
show A
proof (rule classical)
presume "A --> B"
- with aba show A ..
+ with `(A --> B) --> A` show A ..
next
assume "~ A"
show "A --> B"
proof
assume A
- thus B by contradiction
+ with `~ A` show B by contradiction
qed
qed
qed