Why Does Index Position in Kronecker Delta and Tensors Not Always Matter?

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SUMMARY

The discussion centers on the Kronecker delta's index positions in tensors, specifically addressing why the left or right slot index position does not affect its value. Tensors exhibiting this behavior are classified as symmetric. Additionally, it highlights that two index tensors may not be equal due to the significance of index position, particularly in the context of multilinear mappings and metric manifolds, as seen in electrodynamics where mixed components of the field tensor differ.

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  • Understanding of tensor notation and properties
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  • Knowledge of symmetric tensors
  • Basic concepts of multilinear mappings in the context of metric manifolds
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  • Explore the differences between mixed tensor components in electrodynamics
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Homework Statement


kroenecker delta has one upper and one lower index. except from uppper index and lower index,we have 2 slots for the upper index and 2 slots for the lower index(for a 2 index tensor).
Why krenecker delta left or right slot index position doesn't matters?
Also why 2 two index tensors may not be equal because of the peculiarity of left and right slot index position?


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The Attempt at a Solution

 
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helpcometk said:
Why krenecker delta left or right slot index position doesn't matters?

That's just because of the definition. Tensors that behave like this are called symmetric.

helpcometk said:
Also why 2 two index tensors may not be equal because of the peculiarity of left and right slot index position?

I don't understand what this question means.
 
Because of the general definition of a tensor as a multilinear mapping, the order in which the vector spaces and their duals are chosen really matters, especially when the bundle of tensors is defined for a metric manifold (as is the case in relativity).

You will study electrodynamics and discover that the mixed components of the field tensor are all different, that is

[tex]F_{\mu}^{~~\nu} \neq F^{\nu}_{~~\mu}[/tex]

for arbitrary index values.
 

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