So I understand that the X Combinator is defined as X = λx (x S) K
I am also aware of definitions of S and K and I: S = XK K = X(X(X X)) I = SKK
Now I'm wondering how I would go about defining I via the X combinator. Is it simply subtituting S = XK into I = SKKso that we get I = XKKK?
Also, how would I apply X combinator to denote numerals such as 2? The church numerals define 2 as λ f (λ x (f (f x))). I obtained the combinator form of 2 in terms of S, K, and I as S