How to derive Relation between Levi-civita Density and Kronecker's Delta?

[Abir Sarkar]

The Relation between Levi-Civita Density and Kroneckers Delta as follows

$\sum^{3}_{k=1} \epsilon_{mnk} \epsilon_{ijk} = \delta_{mi} \delta_{nj} - \delta_{mj} \delta_{ni}$​

Logically we can satisfy both sides of the expression but Can anyone tell me how to derive this analytically ?

 

[dextercioby]

I don't think you can purely derive it, just consider that the RHS must be a-symmetric in m,n and i,j, so it must be an antisymmetrized product of deltas.