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