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