src/HOL/AxClasses/Tutorial/Semigroup.thy

+(*  Title:      HOL/AxClasses/Tutorial/Semigroup.thy
+    ID:         $Id$
+    Author:     Markus Wenzel, TU Muenchen
+
+Define class "semigroup".
+*)
+
+Semigroup = HOL +
+
+consts
+  "<*>"         :: "['a, 'a] => 'a"             (infixl 70)
+
+axclass
+  semigroup < term
+  assoc         "(x <*> y) <*> z = x <*> (y <*> z)"
+
+end