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Math Help - Proving a function is one-to-one/onto

  1. #1
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    Proving a function is one-to-one/onto

    I have a function:

    f(m,n) = mn

    The domain for this is Z \times Z. The range is Z. How can I prove if it is one-to-one, onto, or both?
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  2. #2
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    Quote Originally Posted by Projectt View Post
    I have a function:
    f(m,n) = mn
    The domain for this is Z \times Z. The range is Z. How can I prove if it is one-to-one, onto, or both?
    It is clearly not one-to-one: f(2,3)=f(3,2).
    Is it onto? If z\in \mathbb{Z} then is it possible that f(?,?)=z?
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  3. #3
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    Ohh, I thought Z was some arbitrary set, not the set of all integers. Thanks.
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