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