(defun total () (lambda x (if (= () x) 0 (+ (hd x) ((total) (tl x)))))) ((total) (cons 3 (cons 7 ()))) (defun prefix* () (lambda x (lambda y (if (= () x) true (if (= y ()) false (if (= (hd x) (hd y)) ((prefix*) (tl x) (tl y)) false)))))) ((prefix*) [1] [1 2]) (defun prefix* (x y) (cond ((= () x) true) ((= y ()) false) ((= (hd x) (hd y)) (prefix* (tl x) (tl y))) (true false))) (prefix* [1 2] [1 2 3])