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Hendrick
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Homework Statement
Simplify/Evaluate these expressions involving the Kronecker delta, using Einstein's summation convention:
a)[tex]\delta_{qr}[/tex][tex]\delta_{rp}[/tex][tex]\delta_{pq}[/tex]
b)[tex]\delta_{pp}[/tex][tex]\delta_{qr}[/tex][tex]\delta_{rq}[/tex]
Homework Equations
[tex]\delta_{ij}[/tex]=0 when i =/= j
[tex]\delta_{ij}[/tex]=1 when i = j
The Attempt at a Solution
a)[tex]\delta_{qr}[/tex][tex]\delta_{rp}[/tex][tex]\delta_{pq}[/tex]
=[tex]\delta_{qp}[/tex][tex]\delta_{pq}[/tex]
=[tex]\delta_{qq}[/tex] = 3 (summation over repeated q)
b)[tex]\delta_{pp}[/tex][tex]\delta_{qr}[/tex][tex]\delta_{rq}[/tex]
=[tex]\delta_{pp}[/tex][tex]\delta_{qq}[/tex]
=(3)(3)
=9
[Am I actually able to evaluate the [tex]\delta_{qr}[/tex][tex]\delta_{rq}[/tex] part before the [tex]\delta_{pp}[/tex] part, I mean you can't do that with matrices... :S]
Thank you