union

(in-package "ACL2")

(defsection std/lists/union
  :parents (std/lists union$)
  :short "Theorems about @(tsee union$) in the @(see std/lists) library."
  (defthm true-listp-of-union-equal
    (equal (true-listp (union-equal x y)) (true-listp y)))
  (defthm true-listp-of-union-equal-type
    (implies (true-listp y) (true-listp (union-equal x y)))
    :rule-classes :type-prescription))