- #1
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Homework Statement
The antisymmetric tensor is constructed from a vector ##\vec a## according to ##A_{ij} = k\varepsilon_{ijk}a_k##.
For which values of ##k## is ##A_{ij}A_{ij} = |\vec a|^2##?
Homework Equations
Identity
##\varepsilon_{ijk}\varepsilon_{klm} = \delta_{il}\delta_{jm}-\delta_{im}\delta_{jl}##
The Attempt at a Solution
##A_{ij}A_{ij} = k^2\varepsilon_{ijk}\varepsilon_{ijm}a_ka_m = k^2\varepsilon_{jki}\varepsilon_{ijm}a_ka_m = k^2(\delta_{jj}\delta_{km}-\delta_{jm}\delta_{kj})a_ka_m = k^2(\delta_{km}-\delta_{km})a_ka_m =0##
Which I obviously shouldn't get but I can't see where I'm making an error.