incr-set prlevel 1
if #0=2 START 
incr-set prlevel -1

;;; Usage:
;;; 	<j_from_lambda lambda j
;;;
;;; computes j = 2^8 (lambda^2-lambda+1)^3 / lambda^2 (lambda-1)^2
incr-set prlevel 1
jump END
;;;
;;; Parameters:
;;;		lambda = a number (from the base field)
;;; Output values:
;;;		j = 1x1 matrix containing a number.
;;; 
;;; This is the function invariant under lambda --> 
;;;		lambda, 1/lambda, 1-lambda, 1/(1-lambda) 
;;; 	lambda/(lambda-1) , (lambda-1)/lambda.
;;;
; created May 3, 1989
START:
poly #2 ((2^8)*((#1)^2-#1+1)^3)/(((#1)^2)*(#1-1)^2)
poly num (2^8)*((#1)^2-#1+1)^3
poly denom (((#1)^2)*(#1-1)^2)
type num
type denom
END:
incr-set prlevel -1

$;;;;;;;; EXAMPLE SECTION ;;;;;;;;;;;;;;;;;;;;;;;;;
<ring 1 x r
set char0 1
<j_from_lambda
<j_from_lambda -1 j
type j
