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Units group of Z modulo

  1. Nov 7, 2011 #1
    I came accross this question. Is the group (ℤ/34/ℤ)x cyclic?
    We haven't discussed the theorem in class that any units group of Z modulo n is iff n = 1, 2, 4, pk and 2pk (where p is an odd prime). But thanks to Deveno I know about it. So in this case, p =17 works, so the group is cyclic?

    but is there a different way to show it besides using brute force .
  2. jcsd
  3. Nov 7, 2011 #2
    Re: (ℤ/34/ℤ)^x

    BTW, p doesn't have to be equal to 4k+3 for this to be true, correct?
    Last edited: Nov 7, 2011
  4. Nov 8, 2011 #3
    Re: (ℤ/34/ℤ)^x

    I guess I can show that ℤ/34/ℤx is ≈ to ℤ/17/ℤx and by the field's finite subgroup theorem, it is a cyclic.
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