Null NIL

• Defined in theory: Kif-lists
• Source code: kif-lists.lisp

Slots on this null:

Documentation:

The list with no items, of length 0. All null lists are equal to this object, called NIL.

Instance-Of: Null

Other Related Axioms:

(<- (Butlast ?List)
    (Cond ((Null ?List) Bottom)
          ((Null (Rest ?List)) Nil)
          (True (Cons (First ?List) (Butlast (Rest ?List))))))

(<- (Remove ?X ?List)
    (Cond ((Null ?List) Nil)
          ((And (= ?X (First ?List)) (List ?List))
           (Remove ?X (Rest ?List)))
          ((List ?List) (Cons ?X (Remove ?X (Rest ?List))))))

(<- (Subst ?X ?Y ?Z)
    (Cond ((= ?Y ?Z) ?X)
          ((Null ?Z) Nil)
          ((List ?Z)
           (Cons (Subst ?X ?Y (First ?Z)) (Subst ?X ?Y (Rest ?Z))))
          (True ?Z)))