It is shown that a conjecture of E. A. Rakhmanov is true concerning the zer
o distribution of orthogonal polynomials with respect to a measure having a
discrete real support. We also discuss the case of extremal polynomials wi
th respect to some discrete L-p-norm, 0 < p less than or equal to infinity,
and give an extension to complex supports.
Furthermore, we present properties of weighted Fekete points with respect t
o discrete complex sets, such as the weighted discrete transfinite diameter
and a weighted discrete Bernstein-Walsh-like inequality.