Proving Tensor Commutation: T^abc S_b vs S_b T^abc

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SUMMARY

The discussion focuses on proving the commutation relation between tensors T^{abc} and S_{b}. It establishes that T^{abc}S_{b} equals S_{b}T^{abc} under the condition that both tensors are commutative variables with Grassmann parity equal to 1. However, it concludes that T^{abc}S_{bd} does not equal S_{bd}T^{abc} in general, highlighting the importance of the specific indices involved in tensor operations.

PREREQUISITES
  • Understanding of tensor notation and operations
  • Familiarity with Grassmann algebra and parity concepts
  • Knowledge of commutative properties in algebra
  • Basic principles of linear algebra and vector spaces
NEXT STEPS
  • Study the properties of Grassmann variables in depth
  • Learn about tensor algebra and its applications in physics
  • Explore the implications of tensor commutation in differential geometry
  • Investigate specific examples of non-commutative tensor products
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This discussion is beneficial for students and researchers in theoretical physics, particularly those studying tensor calculus, differential geometry, and algebraic structures involving Grassmann variables.

Irid
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Homework Statement


How would you show that

T^{abc}S_{b} = S_{b}T^{abc}

but

T^{abc} S_{bd} \neq S_{bd} T^{abc}

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?
 
Physics news on Phys.org
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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