Yes. The killer is p: . But this got me curious. I finally remembered that the inverse of q: was */ but I was surprised to find that the inverse of */ was q:
*/ b._1 q: */^:_1]12 2 2 3 But this is an error. +/ b._1 |domain error | +/b._1 Granted, the inverse of sum has no meaning. And the inverse of */ to be q: makes a useful tool. But information is lost. (]&.(*/))3 4 2 2 3 So I was thinking that */^:_1 should be an error. Then again, *: b._1 %: (]&.*:)_4 4 4 4 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
