Nonlinear potentials and two weight trace inequalities for general dyadic and radial kernels (2003)
Cascante, C., Ortega, J. M., Verbitsky, I. E.
We study trace inequalities of the type $$ \| T_k f\|_{L^q(d\mu)}\leq C \|f\|_{L^p(d\sigma)}, \qquad f \in L^p(d\sigma), $$ in the ``upper triangle case'' $1 \leq q