- #1

- 762

- 59

I understand the first part to get -E

^{i}, but it's the second line of the next bit I don't understand. I see he wants to get line one to the form he has done so he can use the following identity:

##\varepsilon _{ijk}\varepsilon _{ilm} = \delta _{jl}\delta _{km} - \delta _{jm}\delta _{kl}##

But I'm unsure how he has got there and line 2 to 3 looks a little iffy. I've tried using ##\delta _{ij}\delta _{jk} = \delta _{ik}## but that didn't go very well, and also I've always thought something of the form ##\delta_{i}^{l} ## was the kroneka delta function, so I'm unsure how it would come in here.

If someone can help by putting a couple of inbetween stages in the derivation it would really help my understanding of what is going on and the notation / identities he's used.