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