Open benruijl opened 7 years ago
Here is a FORM implementation with zero-dimensional tables:
* An implementation of prod(n,n1,n2,expr).
S n,n1,n2,x;
Table prod(n?symbol_,n1?int_,n2?int_,x?);
Table ident(x?); * identity function
Fill prod() =
+ theta_(n2-n1) * prod(n,n1,n2-1,x) * ident(x * replace_(n,n2))
+ thetap_(n1-n2)
;
Fill ident() = x;
.sort
* Examples.
CF f;
S i;
L F1 = prod(i,3,6,i);
L F2 = prod(i,3,6,f(i));
P;
.end
F1 =
360;
F2 =
f(3)*f(4)*f(5)*f(6);
It would be nice to have a
prod_
function, which behaves similarly tosum_
.