I have always marveled over copies =: $,: as a dyadic hook, but it suffers from requiring the left argument to be an atom as does your permutations example, whereas mean works well with any shape monadic argument. Mean is also amenable to rank variations, while the others are not so much.
I like your purpose, Dan. -- (B=) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
