library: tweak gcd

[lambda.git] / lambda_library.mdwn

diff --git a/lambda_library.mdwn b/lambda_library.mdwn
index 6441d3b..2e65f5c 100644 (file)
--- a/lambda_library.mdwn
+++ b/lambda_library.mdwn
@@ -236,6 +236,12 @@ and all sorts of other places. Others of them are our own handiwork.
        let Theta = (\u f. f (u u f)) (\u f. f (u u f))  in
 
 
+       ; now you can search for primes, do encryption :-)
+       let gcd = Y (\gcd m n. iszero n m (gcd n (mod m n)))  in ; or
+       let gcd = \m n. iszero m n (Y (\gcd m n. iszero n m (lt n m (gcd (sub m n) n) (gcd m (sub n m)))) m n)  in
+       let lcm = \m n. or (iszero m) (iszero n) 0 (mul (div m (gcd m n)) n)  in
+
+
        ; length for version 1 lists
        let length = Y (\self lst. isempty lst 0 (succ (self (tail lst))))  in