“…As a consequence, the corresponding inner product, the associated orthogonal sequence, and the second kind polynomials will depend on t. at is, P n (x, t) n≥0 will be orthogonal for every value of t, and thus the sequence f n (x, t) n≥1 constructed by using eorem 1 will be Hurwitz for every value of t. In other words, if we consider t as an uncertain parameter, the sequence f n (x, t) n≥1 will be robustly stable. It is worth mentioning that robustly stable families constructed in such a way have been already used in the design of a compensator that robustly stabilizes an interval plant with uncertain time-delay (see [30]) and can also be used for applications in control design.…”