<<scheme/truth-table>>

(define (tautology? procedure arity)
  (not (member #f (map (lambda (row)
                         (car (reverse row)))
                       (truth-table procedure arity)))))

<<scheme/tautology?>>

(unless (tautology? (lambda (p) (or p #t)) 1) (raise #f))
(unless (tautology? (lambda (p q) (or p q #t)) 2) (raise #f))
(unless (tautology? (lambda (p q r) (or p q r #t)) 3) (raise #f))

(when (tautology? (lambda (p) (or p)) 1) (raise #f))
(when (tautology? (lambda (p q) (or p q)) 2) (raise #f))
(when (tautology? (lambda (p q r) (or p q r)) 3) (raise #f))

"tests passed"