“…Algorithm 2 removes the switches SW ( , , , ), where , and , belong to the same set of , , and from PSB ( , ), = + + . For example, Figure 13(a) shows a semiuniversal switch block PSB SU (2, 2, 2, 4), which is equal to a universal PSB (2,8) in Figure 13(b) minus some prohibited switches in Figure 13(c). That is to say, a semiuniversal switch block PSB SU ( , , , ) contains a partial topology of the universal switch block PSB ( , ).…”