Right; you just add definitions you need like let Y = \f. (\x. x x) (\x. f (x x)) in program-using-Y which is the slightly more legible version of (\Y. progr

Right; you just add definitions you need like let Y = \f. (\x. x x) (\x. f (x x)) in program-using-Y which is the slightly more legible version of (\Y. program-using-Y) (\f. (\x. x x) (\x. f (x x))