I'm studying Group Theory by myself and I face the basic concept regarding superscript and subscript indices on the Kronecker delta tensor:

What is the meaning (or difference) of these symbols?

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- Feb 8th 2009, 12:43 PMintervoxelIndex notation meaning
I'm studying Group Theory by myself and I face the basic concept regarding superscript and subscript indices on the Kronecker delta tensor:

What is the meaning (or difference) of these symbols? - Feb 8th 2009, 01:28 PMHallsofIvy
I thought I knew what the "Kroneker delta" was but it certainly isn't a tensor! [itex]\delta_{\alpha\beta}[/itex] is the array that is 1 if [itex]\alpha= \beta[/itex] and 0 otherwise. That doesn't depend on any coordinate system and so does not transform as a tensor would under a change of coordinate systems.

- Feb 9th 2009, 11:23 AMintervoxel
Actually what I'm trying to understand are the following expressions which appeared when studying the SU(2) group: