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Homework Help: Another group theory question

  1. Nov 9, 2006 #1
    Could you also help me start this question

    show that if a^2 = e for all a in G then G must be commutative. (where e is the identity)

  2. jcsd
  3. Nov 9, 2006 #2


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    What does aabb equal? What does abab equal?
  4. Nov 9, 2006 #3
    umm ok .. so i get that aabb must also =e .. but im not sure how to get abab
    Last edited: Nov 9, 2006
  5. Nov 9, 2006 #4


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    Just show that ab = ba.

    That's what you're doing. Start from there.
  6. Nov 9, 2006 #5


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    It's (ab)(ab), so you know aabb = abab. Can you finish that?
  7. Nov 12, 2006 #6
    thanks :).. i got it now
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