x u&.v y ↔ vi (v x) u (v y)
([: /: ":)&.>a,b ┌─────────┬─────────┐ │1 0 2 3 4│4 2 3 1 0│ └─────────┴─────────┘ <([: /: ":)>a,b ┌──────────────────────┐ │5 1 10 0 2 8 9 3 7 4 6│ └──────────────────────┘ Why are these different? Linda ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm