MEMBER-EQUAL using HONS-EQUAL for each equality check
Function: hons-member-equal
(defun hons-member-equal (x y) (declare (xargs :guard t)) (mbe :logic (member-equal x y) :exec (cond ((atom y) nil) ((hons-equal x (car y)) y) (t (hons-member-equal x (cdr y))))))