(define count-reflexive-pairs (lambda (rel) (cond [(null? rel) 0] [(eq? (caar rel) (cadar rel)) (+ 1 (count-reflexive-pairs (cdr rel)))] [else (count-reflexive-pairs (cdr rel))]))) (define count-reflexive-pairs (lambda (rel) (cond [(null? rel) 0] [else (+ (if (eq? (caar rel) (cadar rel)) 1 0) (count-reflexive-pairs (cdr rel)))]) (define count-reflexive-pairs (lambda (rel) (if (null? rel) 0 (let ([refl-from-cdr (count-reflexive-pairs (cdr rel))]) (if (eq? (caar rel) (cadar rel)) (+ 1 refl-from-cdr) refl-from-cdr)))))