src/HOL/Power.thy
changeset 3390 0c7625196d95
child 4628 0c7e97836e3c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Power.thy	Tue Jun 03 10:56:04 1997 +0200
@@ -0,0 +1,25 @@
+(*  Title:      HOL/Power.thy
+    ID:         $Id$
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
+    Copyright   1997  University of Cambridge
+
+The (overloaded) exponentiation operator, ^ :: [nat,nat]=>nat
+Also binomial coefficents
+*)
+
+Power = Divides + 
+consts
+  binomial :: "[nat,nat] => nat"      ("'(_ choose _')" [50,50])
+
+primrec "op ^" nat
+  "p ^ 0 = 1"
+  "p ^ (Suc n) = (p::nat) * (p ^ n)"
+  
+primrec "binomial" nat
+  binomial_0   "(0     choose k) = (if k = 0 then 1 else 0)"
+
+  binomial_Suc "(Suc n choose k) =
+                (if k = 0 then 1 else (n choose pred k) + (n choose k))"
+
+end
+