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