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