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A kind of Tensor notation?

  1. Nov 10, 2011 #1
    What is meant by things like:

    [tex]R_{[abc]}[/tex]

    and also things like:

    [tex]\nabla_{[a\nabla_b]}[/tex]

    Where you have square brackets in the subscript? Thx
     
  2. jcsd
  3. Nov 10, 2011 #2

    Matterwave

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    It means the anti-symmetric part of that tensor (or, in other words, to anti-symmetrize that tensor).

    For example,
    [tex]A_{[ab]}=\frac{1}{2}(A_{ab}-A_{ba})[/tex]
     
  4. Nov 11, 2011 #3
    Ah yes, thanks matterwave, I guess (ab) is the symmetric part then
     
  5. Nov 11, 2011 #4

    George Jones

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    Yes.
     
  6. Nov 11, 2011 #5

    dextercioby

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    The weighing factor is a matter of convention. For example, some people write

    [tex] F_{\mu\nu}=2\partial_{[\mu}A_{\nu]} [/tex]

    while others


    [tex] F_{\mu\nu}=\partial_{[\mu}A_{\nu]} [/tex]

    in case of the e-m fields.
     
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