“…A first family of results deals with the assumption, originally stated in [40], of bounded membership-function time derivatives, i.e., existence of known scalars φ i such that |μ i (z)| ≤ φ i . Results in this line appear in, for instance, [66]. Although the assumption is understandable for stability results, when z ≡ x, which is the case in nonlinear systems modelled as TS ones, it is more questionable for stabilization as, by chain rule, dµi(x) dt = ∂µi ∂x Tẋ andẋ can contain the to-be-designed control action in a general case, so the validity region of the obtained controller must be checked a posteriori, see discussion in [67].…”