🚀 go-pugleaf

Here's another quiz question:  (actually, this one is really tough as
far as I can tell, and I don't have a solution.)
produce an APL expression that computes the determinant of a matrix.

N.B. - I'm looking for an expression, not a function, so looping and
recursion are out.

I have a (very) partial solution - it works only for non-singular matrices
that would never have a zero on the diagonal in a left-to-right series of
pivoting operations.

Iverson proposed an operator for determining determinants and permanents
(sp?) (pigeon?) in a paper a while back, but using that would be cheating.

			      - Greg Johnson
				U Wis - Madison