In this file we derive the Y combinator, one of the fundamental results of recursive procedure theory. You already know that in some cases it is not necessary to give a procedure a name. For example, ((lambda (x) (+ x 1)) 6) adds 1 to 6 without naming the procedure that does it. But, what about a recursive procedure? For example, (define fact (lambda (n) (if (zero? n) 1 (* n (fact (- n 1)))))) whi