2012/1/6 Roger Hui <rogerhui.can...@gmail.com> > See http://www.jsoftware.com/jwiki/Essays/Under for examples of under. > > I see gi is defined now
f&.g y [image: $\leftrightarrow$] gi f g y x f&.g y [image: $\leftrightarrow$] gi (g x) f (g y) where gi is the inverse of g . "Under" elucidates the important but often mysterious concept of duality in mathematics. Sometime long time ago I remember speculating what this gi was. Either it was not defined in the text or I failed to find it. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
