For 0 < a < oo let Ta f denote one of the operatorsWe characterize the pairs of weights (u, v) [4,16]. As an application we give lower bounds for convolutions d~ * f, where dp is a radially decreasing function.
for which Ta is a bounded operator from LP (v) to Lq (u), 0 < p < q < cr This extends to a > 0 the norm inequalities for tr = 0 in