Thanks to all, especially Roger, for the dyadic fork examples. I regard the tautologies as a bit meta, but I do like >. - <. . I had a more complicated example along the same lines.
Before posing the question, I followed Oleg's advice in that I eyeballed the dyads in J Phrases: almost all use [ ] @ @: or constant functions. Best wishes, John ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
