--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc-src/Intro/gate2.thy	Wed Nov 10 05:06:55 1993 +0100
@@ -0,0 +1,8 @@
+Gate2 = FOL +
+consts  "~&"     :: "[o,o] => o" (infixl 35)
+        "#"      :: "[o,o] => o" (infixl 30)
+        If       :: "[o,o,o] => o"       ("if _ then _ else _")
+rules   nand_def "P ~& Q == ~(P & Q)"    
+        xor_def  "P # Q  == P & ~Q | ~P & Q"
+        If_def   "if P then Q else R == P&Q | ~P&R"
+end