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