Tensor commutation

  • Thread starter Irid
  • Start date
  • #1
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Homework Statement


How would you show that

[itex] T^{abc}S_{b} = S_{b}T^{abc} [/itex]

but

[itex] T^{abc} S_{bd} \neq S_{bd} T^{abc} [/itex]

in general?

The Attempt at a Solution


If I write out the sums explicitly, they appear totally the same to me. Any hints or ideas please?
 

Answers and Replies

  • #2
dextercioby
Science Advisor
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You must be joking, right ? If T and S are commutative variables (Grassmann parity =1), then it doesn't matter in which order you write those two sums.
 

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