How to evaluate a kronecker delta and levi civita

Question

How to evaluate ij with Einstein summation notation. I don't really understand what this is asking: is it asking for a number or a simplification using letters or?

Answer 1

You have a double sum in $i$ and $j$. Only the terms with $i=j$ survive, otherwise $\delta_{ij}=0$. Hence you are left with $\epsilon_{iik}$ (this is a sum in $i$) but by definition these symbols, they are equal to zero if two indices coincide. Your convolution is thus equal to zero.