The purpose of this paper is to present full
proofs for the important results on discrete
Muckenhoupt weights. The first states that if w
is a weight in the Muckenhoupt class A_p for
l^p, then w^r belongs to A_p for all r
sufficiently close to 1 ("Wackelsatz").
The second result is Stechkin's inequality,
which gives an upper estimate for the multiplier
norm on l^p(w)(w in A_p) through the L^infty
norm and the total variation of the multiplier.
Although both results are certainly well-known
to specialists, we have not found self-contained
proofs.
to