For the sets M∗p(R), 1 p < ∞, of positive finite Borel measures μ on the real axis with the set of algebraic polynomials
P dense in Lp(R, dμ), we establish a majorization principle of their “boundaries,” i.e. for every μ ∈M∗p(R) there exists
ν ∈M∗p(R) \ q>pM∗q (R) such that dμ/dν 1. A corresponding principle holds for the sets W∗p(R), p >0, of non-negative
upper semi-continuous on R functions (weights) w such that P is dense in the space C0wp: For every w ∈ W∗p(R) there exists
ω ∈W∗p(R) \ q
Keywords :
Measures , C0w-spaces , polynomial approximation , Weighted approximation , Lp-spaces