From: Jim Pryor <profjim@jimpryor.net>
Date: Thu, 30 Sep 2010 18:28:25 +0000 (-0400)
Subject: tweaked arithmetic
X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=e24b3eb555211cb2d9af17355b305313ba0eaf7a

tweaked arithmetic

Signed-off-by: Jim Pryor <profjim@jimpryor.net>
---

diff --git a/arithmetic.mdwn b/arithmetic.mdwn
index f7406ccb..cac56f20 100644
--- a/arithmetic.mdwn
+++ b/arithmetic.mdwn
@@ -198,7 +198,7 @@ Here are a bunch of pre-tested operations for the untyped lambda calculus. In so
 		))  in
 
 
-	; Curry's fixed point combinator
+	; Rosenbloom's fixed point combinator
 	let Y = \f. (\h. f (h h)) (\h. f (h h)) in
 	; Turing's fixed point combinator
 	let Z = (\u f. f (u u f)) (\u f. f (u u f))  in
@@ -239,3 +239,23 @@ Here are a bunch of pre-tested operations for the untyped lambda calculus. In so
 			; and consume is
 			(\p. p get_2nd p)  in ; or
 -->
+
+<!--
+	gcd
+	pow_mod
+
+
+	show Oleg's definition of integers:
+		church_to_int = \n sign. n
+		church_to_negint = \n sign s z. sign (n s z)
+
+		; int_to_church
+		abs = \int. int I
+
+		sign_case = \int ifpos ifzero ifneg. int (K ifneg) (K ifpos) ifzero
+
+		negate_int = \int. sign_case int (church_to_negint (abs int)) zero (church_to_int (abs int))
+
+	for more, see http://okmij.org/ftp/Computation/lambda-arithm-neg.scm
+
+-->