In the present note we characterize the function space $\dot{X}_{r}$, which is the set of pointwise multipliers which map $L^{2}$ into $\dot{H}^{-r}$. To this end, we use wavelets and capacity.
Funct. Approx. Comment. Math.
43(2):
109-116
(December 2010).
DOI: 10.7169/facm/1291903392
