Abstract:
We study the $L_{p_1}\times L_{p_2}\times\ldots\times L_{p_k}$ boundedness of generalized multilinear fractional integrals. An O'Neil type inequality for a $k$-linear integral operator is proved. Using an O'Neil type inequality for a $k$-linear integral operator, we obtain a pointwise rearrangement estimate of generalized multilinear fractional integrals. By way of application we prove a Sobolev type theorem for these integrals.