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Homework Help: Subgroups of External Direct Products

  1. Apr 9, 2006 #1
    Problem "Find all subgroups of order 3 in Z9 x Z3"

    Using an external direct product I came out with the elements:

    0... to 0,9
    1.... to 1,9
    2.... to 2,9

    With subgroups:


    Just looking for some confirmation if I have done this correctly. I was reading my book and it was lacking a definition/example that I felt like I fully understood.
  2. jcsd
  3. Apr 9, 2006 #2


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    This is 99% correct, it's just that you've given subgroups of Z3 x Z9, not Z9 x Z3.
  4. Apr 9, 2006 #3
    Wow... nice catch. Now I'm wondering if I can just write on top of the page to switch everything to the other side or if I should re-write the page :(.

    I'll just write a little snippet about it and then re-write the subgroups. That seems to the best way about fixing this. Thanks for the help.
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