“…First we note that an optimal solution (x * , t * ) = (x * 1 , x * 2 , · · · , x * N , t * 1 , t * 2 , · · · , t * N )(where t i , i = 1, 2, · · · , N , are defined by (15), (16), (30), (31) and (32)) of Problem Max exists. This follows from: (i) the fact that each U i , i ∈ N , is concave and the space of the constraints described by Eqs.…”