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Math Help - help with sets and logic

  1. #1
    Senior Member
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    Cool help with sets and logic

    I want to show if
    |AxB|=|A|
    what can we conclude about A and B, and justify it.

    I have that

    |AxB|=|A|
    |A||B|=|A|
    |B|=|A|/|A|
    |B|=1
    so the cardinality of B is 1

    Is this ok?
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  2. #2
    MHF Contributor

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    Quote Originally Posted by Sneaky View Post
    I want to show if
    |AxB|=|A| what can we conclude about A and B, and justify it.
    I have that
    |AxB|=|A|
    |A||B|=|A|
    |B|=|A|/|A|
    |B|=1
    so the cardinality of B is 1
    Once again, have you failed to state important bits of information?

    Do you know that A\ne \emptyset~?
    If not, you need to discuses that possibility.
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