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 成人高等教育 / 离散数学(上)
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设 A={1, 2, 4, 6}, 则关系 R={<x, y>|x, y∈Ax/y∈A}等于:

  • A、

    A×A - {<1,1>};  

  • B、

    {<1,2>,<2,1>};  

  • C、

    {<1,1>,<2,2>,<4,4>,<6,6>,<2,1>,<4,2>,<4,1>};  

  • D、

    {<1,2>,<2,2>,<4,2>,<6,2>}.

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