离散数学中有四个元素的集合能确定多少种相容关系

Question

如题所述

Answer 1

设A={1，2，3，4}，A上有8个相容（自反，对称）关系：
{(1,1),(2,2),(3,,3),(4,4)};
{(1,1),(2,2),(3,,3),(4,4),(1,2),(2,1)};
{(1,1),(2,2),(3,,3),(4,4),(1,3),(3,1)};
{(1,1),(2,2),(3,,3),(4,4),(2,3),(3,2)};
{(1,1),(2,2),(3,,3),(4,4),(1,2),(2,1),(1,3),(3,1)};
{(1,1),(2,2),(3,,3),(4,4),(2,3),(3,2),(1,3),(3,1)};
{(1,1),(2,2),(3,,3),(4,4),(1,2),(2,1),(2,3),(3,2)};
{(1,1),(2,2),(3,,3),(4,4),(1,2),(2,1),(2,3),(3,2),(1,3),(3,1)};本回答被提问者采纳

Answer 2

ls正解