L_p Christoffel functions, L_p universality, and Paley-Wiener spaces

Let ω be a regular measure on the unit circle in ℂ, and let p > 0. We establish asymptotic behavior, as n→∞, for the L_p Christoffel function (formula presented.) at Lebesgue points z on the unit circle in ℂ, where ω′ is lower semi-continuous. While bounds for these are classical, asymptotics have never been established for p ≠ 2. The limit involves an extremal problem in Paley-Wiener space. As a consequence, we deduce universality type limits for the extremal polynomials, which reduce to random-matrix limits involving the sinc kernel in the case p = 2. We also present analogous results for L_p Christoffel functions on [−1, 1].