00100	(DE LINEMAX (U LINE ALPHA BETA)
00200	(COND ((NULL U) (CONS ALPHA LINE))
00300	(T
00400	((LAMBDA (S)
00500	(COND ((NOT (GREATERP (CAR S) ALPHA))
00600	(LINEMAX (CDR U) LINE ALPHA BETA))
00700	((LESSP (CAR S) BETA)
00800	(LINEMAX (CDR U) (CONS (CAR U) (CDR S)) (CAR S) BETA))
00900	(T
01000	(CONS BETA LINE)
01100	)))
01200	(COND ((TER (RECTIFY (CAR U)) ALPHA BETA) (IMVAL (CAR U)))
01300	(T
01400	(LINEMIN (SUCCESSORS (CAR U)) (CONS BETA @BETA-CUTOFF) ALPHA BETA)
01500	))))))
01600	
01700	(DE LINEMIN (U LINE ALPHA BETA)
01800	(COND ((NULL U) (CONS BETA LINE))
01900	(T
02000	((LAMBDA (S)
02100	(COND ((NOT (GREATERP (CAR S) ALPHA))
02200	(CONS ALPHA LINE))
02300	((LESSP (CAR S) BETA)
02400	(LINEMIN (CDR U) (CONS (CAR U) (CDR S)) ALPHA (CAR S)))
02500	(T
02600	(LINEMIN (CDR U) LINE ALPHA BETA)
02700	)))
02800	(COND ((TER (RECTIFY (CAR U)) ALPHA BETA) (IMVAL (CAR U)))
02900	(T
03000	(LINEMAX (SUCCESSORS (CAR U)) (CONS ALPHA @ALPHA-CUTOFF) ALPHA BETA)
03100	)))))))