(symbol-equiv x y) recognizes symbols that are identical under symbol-fix.
Function:
(defun symbol-equiv$inline (x y) (declare (xargs :guard (and (symbolp x) (symbolp y)))) (equal (symbol-fix x) (symbol-fix 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 x x-equiv) (equal (symbol-fix x) (symbol-fix x-equiv))) :rule-classes (:congruence))
Theorem:
(defthm symbol-fix-under-symbol-equiv (symbol-equiv (symbol-fix x) x) :rule-classes (:rewrite :rewrite-quoted-constant))
Theorem:
(defthm symbol-equiv-implies-equal-symbol-name-1 (implies (symbol-equiv x x-equiv) (equal (symbol-name x) (symbol-name x-equiv))) :rule-classes (:congruence))