For sequences u= (u_m), v=( v_m), define the sequence w by w_j= \sum_{m≥0} u_m _{m+j}. Let 0<p<1. If u belongs to l_1 and v to l_p, does w belong l_p?

In case p≥1, it is a classical result on convolution (discrete Young inequality)

01 May 2017 998 1 View