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