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Homework Help: Linear Algebra help - !

  1. Nov 18, 2006 #1
    Linear Algebra help -urgent!

    Hi,
    I'm doing a bit of self learning on Linear Algebra but I'm kinda confused with the information given on odd and even permutations?

    How do you determine whether a permutation is odd or even?

    For example, the book has given some examples such as:

    (1 2 3 4) is odd, (1 3)(2 4) is even? :confused:

    Can someone help please? Thank you!
     
  2. jcsd
  3. Nov 18, 2006 #2

    radou

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    Homework Helper

    Try to count the 'steps' you need to do a permutation and see if the number is odd or even.
     
  4. Nov 18, 2006 #3
    A permutation is even if it's the product of an even number of 2-cycles. That's why (1 3)(2 4) is even. A permutation is odd if it isn't even. (1 2 3 4 ) written as two cycles would be (1 4)(1 3)(1 2) which is odd.
     
  5. Nov 18, 2006 #4
    Thanks guys! I get it now :biggrin:
     
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