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