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