Positive interpolation operators , where , defined by
for weights , are introduced. Here is the kernel of degree at most n-1 in x, t for the partial sums of the orthogonal expansions with respect to , and and are the abcissas and weights in the Gaussian quadrature of order n. Their basic properties are established, and their convergence is proved for and a certain class of weights on the whole real line. P. G. Nevai [Orthogonal polynomials, Mem. Am. Math. Soc. 213 (1979; Zbl 0405.33009)] has considered the special case and weights on [-1,1].