Statistical and Economic Approaches to Legal History (Forthcoming in UNIV. OF ILL. L. REV. (2002)) Daniel Klerman USC Law and Economics & Law and Public Policy Research Paper No. 02-6 LAW AND ECONOMICS RESEARCH PAPER SERIES
4. 广义笛卡尔积 (Extended Cartesian Product Extended Cartesian Product) z R – n目关系,k1个元组 z S – m目关系,k2个元组 z R×S – 列:(n+m)列的元组的集合 z 元组的前n列是关系R的一个元组 z 后m列是关系S的一个元组 – 行:k1×k2个元组