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