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Math Help - Injective Function

  1. #1
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    Injective Function

    Hi. Is a function injective iff EVERY element in the domain is mapped to a distinct element in the codomain:

    For example:

    A={1,2,4} B={Q, W, S, T}

    1 is mapped to Q
    2 is mapped to W
    4 is not mapped.

    Is this considered an injective function from A to B?
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  2. #2
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    Quote Originally Posted by jayshizwiz View Post
    Hi. Is a function injective iff EVERY element in the domain is mapped to a distinct element in the codomain:

    For example:

    A={1,2,4} B={Q, W, S, T}

    1 is mapped to Q
    2 is mapped to W
    4 is not mapped.

    Is this considered an injective function from A to B?
    The given function is not a function from A to B, but rather a function from {1,2} to B. So, no.
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  3. #3
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    The given function is not a function from A to B, but rather a function from {1,2} to B. So, no.
    Thanks.
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  4. #4
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    Notice that the difficulty is not with "injective" but calling it a function from A to B at all.
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