“…The same mistake was also made in the same context by Bla_ zewicz and Drozdowski in [11]. Beaumont, Legrand, and Robert [7,8] proved, for the single-level tree networks with front-end processors, that in any optimal solution the processors are ordered by decreasing bandwidth, they all participate in the computation, and all finish their execution at the same time. Beaumont, Legrand, and Robert also proposed asymptotically optimal multi-round algorithms.…”