1. ## Suffix Notation

Simplify delta(ij)delta(ij). The (ij) parts should be read as subscripts to the delta.

Can anyone give me any guidance on how to do this?

2. Originally Posted by Yerobi
Simplify delta(ij)delta(ij). The (ij) parts should be read as subscripts to the delta.

Can anyone give me any guidance on how to do this?
$\delta_{ij} \delta_{ij} = \sum_{i,j = 1}^n \delta_{ij} \delta_{ij}$
by the Einstein convention.

Now, you know that $\delta_{ij} = 1$ only if i = j, so what is the sum of this series? (ie. how many times in the above sum do we get i = j?)

-Dan

3. 'n' number of times?

4. I'm just a bit confused on what form the answer should take? Will it be a constant?