diff -r b091e0abb894 -r 56cf3a9a2693 programs/prove1.scala
--- a/programs/prove1.scala	Tue Nov 12 01:53:41 2013 +0000
+++ b/programs/prove1.scala	Tue Nov 12 02:13:22 2013 +0000
@@ -37,7 +37,7 @@
 }
 
 def partitions[A](ls: List[A]): List[(A, List[A])]  = 
-  ls.map (s => (s, ls - s))
+  ls.map (s => (s, ls diff List(s)))
 
 def prove1(lhs: List[Form], rhs: Form, sc: () => Unit) : Unit = 
   rhs match {
@@ -104,7 +104,7 @@
 
 
 val Chr = "Christian"
-val HoD = "Michael Luck"
+val HoD = "Peter"
 val Email = Pred("may_btain_email", List(Const(Chr)))
 val AtLib = Pred("is_at_library", List(Const(Chr)))
 val Chr_Staff = Pred("is_staff", List(Const(Chr)))