Fixtype of words.
Function:
(defun word-equiv$inline (acl2::x acl2::y) (declare (xargs :guard (and (wordp acl2::x) (wordp acl2::y)))) (equal (word-fix acl2::x) (word-fix acl2::y)))
Theorem:
(defthm word-equiv-is-an-equivalence (and (booleanp (word-equiv x y)) (word-equiv x x) (implies (word-equiv x y) (word-equiv y x)) (implies (and (word-equiv x y) (word-equiv y z)) (word-equiv x z))) :rule-classes (:equivalence))
Theorem:
(defthm word-equiv-implies-equal-word-fix-1 (implies (word-equiv acl2::x x-equiv) (equal (word-fix acl2::x) (word-fix x-equiv))) :rule-classes (:congruence))
Theorem:
(defthm word-fix-under-word-equiv (word-equiv (word-fix acl2::x) acl2::x) :rule-classes (:rewrite :rewrite-quoted-constant))
Theorem:
(defthm equal-of-word-fix-1-forward-to-word-equiv (implies (equal (word-fix acl2::x) acl2::y) (word-equiv acl2::x acl2::y)) :rule-classes :forward-chaining)
Theorem:
(defthm equal-of-word-fix-2-forward-to-word-equiv (implies (equal acl2::x (word-fix acl2::y)) (word-equiv acl2::x acl2::y)) :rule-classes :forward-chaining)
Theorem:
(defthm word-equiv-of-word-fix-1-forward (implies (word-equiv (word-fix acl2::x) acl2::y) (word-equiv acl2::x acl2::y)) :rule-classes :forward-chaining)
Theorem:
(defthm word-equiv-of-word-fix-2-forward (implies (word-equiv acl2::x (word-fix acl2::y)) (word-equiv acl2::x acl2::y)) :rule-classes :forward-chaining)