I am following Pavel Grinfield's Tensor Calculus book, in page-137, he shows this remarkable equation:
$$ \epsilon_{rst} \cdot \epsilon^{ijk}=d_{rst}^{ijk} = \begin{vmatrix} \delta_r^i & \delta_s^i & \delta_t^i \\ \delta_r^j & \delta_s^j& \delta_t^j\\ \delta_r^k &\delta_s^k & \delta_t^k \end{vmatrix}$$
This is the definition of determinant given in his book:
$$ |A| = \delta_{rst}^{ijk} \frac{a_i^r a_j^s a_k^t}{3!}$$
Note: $\epsilon_{ijk}$ and $\epsilon_{rst}$ are permutation symbols.
Here is my attempt at proving the fact:
Call: $$B=\begin{bmatrix} \delta_r^i & \delta_s^i & \delta_t^i \\ \delta_r^j & \delta_s^j& \delta_t^j\\ \delta_r^k &\delta_s^k & \delta_t^k \end{bmatrix}$$
Then,
$$|B|= \frac{1}{3!}\delta_{rst}^{ijk} (\delta_{p(i)}^{p(r)}\delta_{p(j)}^{p(s)}\delta_{p(k)}^{p(t)})$$
Where $p$ is a function which maps the index set in the following way : $p(1)=i, p(2)=j,p(3)=k$.. now I don't get how to simplfy..
Edit: Ok, everyother exercise in the proceeding section is based on this..