(1)(证明略)由 R 的定义可得
R = {<(1,1),(1,1)>, <(1,2),(1,2)>, <(1,2),(2,1)>, <(2,1),(1,2)>, <(2,1),(2,1)>,
<(1,3),(3,1)>, <(3,1),(1,3)>, <(1,3),(2,2)>, <(2,2),(1,3)>, <(2,2),(3,1)>,
……, <(2,2),(2,2)>, ……, <(3,3),(3,3)>, …… , <(4,4),(4,4)>};
(2)按等价关系(和数的大小)导出的划分是
{<(1,1),(1,1)>}, {<(1,2),(1,2)>, <(1,2),(2,1)>, <(2,1),(1,2)>,<(2,1),(2,1)>},
{<(1,3),(3,1)>, <(3,1),(1,3)>, <(1,3),(2,2)>, <(2,2),(1,3)>, <(2,2),(3,1)>,
……, <(2,2),(2,2)>}, ……,
{<(3,4), (3,4)>, <(4,3), (4,3)>, <(3,4), (4,3)>, <(4,3), (3,4)>}, {<(4,4),(4,4)>}。
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