Hi, I am currently working my way through the paper "Function Reactive Programming Continued", which is about yampa. On page 55 (page 5 in the pdf) "par" with the signature: par :: Functor col => (forall sf . (a -> col sf -> col (b, sf))) -> col (SF b c) -> SF a (col c) is introduced. So the resulting signal function (of type SF a (col c)) takes its input (of type a) and puts it into the first argument of par together with its second argument (col (SF b c)) to receive a collection of input/signal pairs (col (b, sf)). Correct? My questions: 1. Shouldn't be the signature of the first argument be: a -> col (SF b c) -> col (b, (SF b c)) I mean it receives the second argument of par as its second argument?!? 2. When the collection of input signal/pairs is received (col (b, sf)), the b is applied to sf, correct? Why not directly return the result of this application? I hope I was able to state clear enough questions ... Thanks! Nathan