Abstract:
For polynomials in the Price system, we establish an inequality of different metrics in the Lorentz spaces. Applying this inequality, we prove a Hardy–Littlewood theorem for theFourier–Price series with GM sequences of coefficients in the two-parameter Lorentz spaces and in the Nikol’skii–Besov spaces with a Price basis. We also study the behavior of the best approximations of functions by Price polynomials in the metric of the Lorentz space.