(define (time-minus time1 time2)
(time-carry-correct
(cons (- (car time1) (car time2))
- (- (car time2) (cdr time2)))))
+ (- (cdr time2) (cdr time2)))))
(define (time-plus time1 time2)
(time-carry-correct
(cons (+ (car time1) (car time2))
- (+ (car time2) (cdr time2)))))
+ (+ (cdr time2) (cdr time2)))))
(define-record-type <schedule>