We investigate polynomials satisfying a three-term recurrence relation of the form Bn(x) = (x - n)Bn-1(x) - nxBn-2(x), with positive recurrence coefficients n+1, n (n = 1, 2, . . ...
Let f C[-1, 1] change its convexity finitely many times, in the interval. We are interested in estimating the degree of approximation of f by polynomials which are coconvex with i...