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