Gender in performance, Routledge, 2000, ISBN 0-415-15986-5, p.303 Mike Penner dies at 52; Los Angeles Times sportswriter. Los Angeles Times. 2009-11-29
偶数×整数=偶数(或0) 将0排除在偶数之外使得很多有关偶数的规则、定理都要加上类似的例外。 Penner 1999,第34頁: Lemma B.2.2, The integer 0 is even and is not odd. Penner uses the mathematical symbol ∃, the existential