Help express this λ-calculus function in a non-recursive form?

85 Views Asked by At

The function is fib = λn(IF (n<2) 1 (fib(n-1)+fib(n-2)) (if n<2 then 1, else the sum of the previous two). How do I make it non-recursive? I know it's about making a function H such that H(fib)=H and Y such that H(YH) = fib, but I'm not sure how to do it.