Meaning of totally antisymmetric tensor

  • Thread starter Thread starter homology
  • Start date Start date
  • Tags Tags
    Tensor
Click For Summary
A totally antisymmetric tensor, such as M^{\alpha\beta\gamma}, changes sign when any two indices are exchanged, confirming its antisymmetry. In contrast, a totally symmetric tensor does not change sign under any pair exchange of indices. The discussion highlights a common misunderstanding regarding the properties of these tensors, particularly in relation to the Levi-Civita symbol. A specific example involving the derivative of a tensor, ∂_{\alpha}F_{\beta\gamma}, illustrates the confusion between antisymmetry and symmetry. The clarification emphasizes the importance of correctly applying definitions to avoid errors in tensor analysis.
homology
Messages
305
Reaction score
1
Simple question I am confused on. If I have a tensor M^{\alpha\beta\gamma} that is totally antisymmetric in its indices then is it the case that M changes sign under the exchange of any two indices? And as a followup, a totally symmetric tensor has no sign changes on any pair exchange of indices?

Thanks,

Kevin
 
Physics news on Phys.org
What is your definition of a tensor, and of a totally antisymmetric tensor (resp. totally symmetric tensor)?
 
Damn I think I figured out my problem. I was going off Carroll's definition/discussion of (anti-) symmetry (Spacetime and Geometry) which implies that an exchange of a pair of indices in a totally antisymmetric tensor yields a sign change. This is fine I realize now, what is not fine is the following.

I was looking at \partial_{\alpha}F_{\beta\gamma}. I know that \partial_{\[\alpha}F_{\beta\gamma\]}=0 and I then INCORRECTLY assumed that \partial_{\alpha}F_{\beta\gamma} was totally symmetric which was leading me into errors...argh...noob mistake.
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 4 ·
Replies
4
Views
9K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 10 ·
Replies
10
Views
7K
  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 2 ·
Replies
2
Views
5K