(SETQ GRAPHFNS '(LOSE TER SUCCESSORS))

(DEFUN LOSE (P) (MEMBER (CAR P) (CDR P)))

(DEFUN TER (P) (EQ (CAR P) FINAL))

(DEFUN SUCCESSORS (P) (MAPCAR (FUNCTION (LAMBDA (X) (CONS X P)))
(CDR (ASSOC (CAR P) GRAPH))))

(SETQ FINAL 'F)

(SETQ GRAPH '((A B) (B A C D) (C B D E) (D B C E) (E C D F) (F E)))