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Math Help - surjection question

  1. #1
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    surjection question

    Let f and g be surjections from Z to Z and let h = fg be their product. Must h also be surjective? give a proof or counterexample.

    I'm pretty sure it's false because something to do with f = g but i just can't think of it
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  2. #2
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    solved

    f=g

    h=f^2 h is an element of Z

    let h = -1

    i is not an element of the set Z therefore h is not a surjection
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