The dual space of l_■(0

This paper studies the dual space of the double sequences spaces l_■ when 0p1,0q1, and the dual space when p(={pk}) is an ordered set of quantities in (0,1) besides q1 as well. Hereby we prove that the dual space of l_■ is l_■ in the first circumstance, whereas it is l_■ in the other circumstance where u1,1q+1u=1.