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