Jj. Guadalupe et al., WEIGHTED NORM INEQUALITIES FOR POLYNOMIAL-EXPANSIONS ASSOCIATED TO SOME MEASURES WITH MASS POINTS, Constructive approximation, 12(3), 1996, pp. 341-360
Fourier series in orthogonal polynomials with respect to a measure nu
on [-1, 1] are studied when nu is a linear combination of a generalize
d Jacobi weight and finitely many Dirac deltas in [-1, 1]. We prove so
me weighted norm inequalities for the partial sum operators S-n, their
maximal operator S, and the commutator [M(b), S-n], where M(b) denot
es the operator of pointwise multiplication by b epsilon BMO. We also
prove some norm inequalities for S-n when nu is a sum of a Laguerre we
ight on R(+) and a positive mass on 0.