Resolution Example

>(linres *hounds* *houndc*)
             1.  ((NOT (HOUND X)) (HOWL X))
             2.  ((NOT (LS X)) (NOT (HAVE X Y))
                  (NOT (HOWL Y)))
             3.  ((NOT (HAVE X Y)) (NOT (CAT Y))
                  (NOT (HAVE X Z)) (NOT (MOUSE Z)))
             4.  ((HAVE (JOHN) (A)))
             5.  ((CAT (A)) (HOUND (A)))
             6.  ((LS (JOHN)))
             7.  ((HAVE (JOHN) (B)))
             8.  ((MOUSE (B)))
(  6,  2):   9.  ((NOT (HAVE (JOHN) Y)) (NOT (HOWL Y)))
(  9,  1):  10.  ((NOT (HAVE (JOHN) X)) (NOT (HOUND X)))
( 10,  4):  11.  ((NOT (HOUND (A))))
( 11,  5):  12.  ((CAT (A)))
( 12,  3):  13.  ((NOT (HAVE X (A))) (NOT (HAVE X Z))
                  (NOT (MOUSE Z)))
( 13,  4):  14.  ((NOT (HAVE (JOHN) Z)) (NOT (MOUSE Z)))
( 13,  4):  15.  ((NOT (HAVE (JOHN) (A)))
                  (NOT (MOUSE (A))))
( 14,  4):  16.  ((NOT (MOUSE (A))))
( 14,  7):  17.  ((NOT (MOUSE (B))))
( 17,  8):  18.  NIL
PROVED