“…The lower bound LCD 1 (s, 2) and LCD 2 (s, 2) can be achieved if and only if there are d γ word(s) with γ letters and d γ +1 word(s) with γ + 1 letters among the three words of the indicator function of F. Fang and Mukerjee (2000), Fang et al (2002), Fang et al (2003) and Zhang et al (2005) gave the lower bounds for the centered L 2 -discrepancy on two-level factorials, respectively. For 2 s−k designs and their complementary designs, numerical results which given in the next section show that our lower bound is better than the above lower bounds.…”