“…However, if m is odd, the lower bound in Theorem 2 is more tight. For instance, choose the design in Example 2 of [6] as the initial design d 0 , and assume n 1 = 4, r = 1; then both of the lower bounds in Theorem 1 and Theorem 2 are 53.5134, because m = 14 is even. However, consider the design in Example 1 of [6] as the initial design d 0 , and let n 1 = 2, r = 1, then the lower bounds in Theorem 1 and Theorem 2 are 3.4094 and 3.4307, respectively, since m = 7 is odd.…”