Scheme to elisp

[weber]

Hi everyone...
I started reading the sample chapter of the Friedman's books, but got
stuck trying to rewrite this scheme function in elisp:

(define intersect
        (lambda (set1 set2)
          (letrec
           ((I (lambda (set)
                         (cond
                           ((null? set) (quote ()))
                           ((member? (cat set1) set2)
                                (cons (car set)
                                          (I (cdr set))))
                           (else (I (cdr set)))))))
           (I set1))))

Or in a simplified form, my problem is : why the snippet below does
not work?

(defun f (n)
  (let ((g (lambda (x) (+ 5 x))))
        (g (+ n 1))))

(f 1) -> void-function g

Thanks in advance,
-weber