Hi, anybody can explain how Y combinator work in find fixed point ? say : Y = 'lam' f . ('lam' x . f(xx))('lam' x . f(xx)) X = Y F -> ( 'lam' x .F(xx))('lam' x . F(xx)) -> F(('lam' x . F(xx))('lam' x . F(xx))) <- How can this expression be derived ???????????? ->F X <- And why ? Thanks a lot! Song