Suppose a component of tensor field is described by Bk=εkijϕij. If we define Bk in an Euclidean space then does the rising or lowering of the indices of the Levi-Civita symbol change the sign?
I mean does Bk=εkijϕij=εkijϕij?
Answer
First, if you're going to keep proper track of covariant and contravariant components, you should lower the index on B and make sure the dummy indices are always of opposite types: Bk=εkijϕij. The reason we can be sloppy in Euclidean space is because of how trivial the metric can be. We can always consider our equations in the basis in which gij=δij, in which case it's clear there's really no effective difference between upper and lower indices.
About Levi-Civita in general: If we're talking about the symbol (which I'll denote with a tilde) we typically define the lower-indexed one with components that are positive for even permutations and negative for odd ones (opposite for left-handed coordinate systems). The upper-indexed one is multiplied by the sign of the determinant of the metric: ˜εμ1μ2⋯μn=sgn(g)˜εμ1μ2⋯μn.
Regarding the tensor, its components can generally not only change sign but magnitude as well. This is explained in detail in Sean Carroll's Spacetime and Geometry, for which there is a free online preprint (see in particular pp. 51-52 of Chapter 2). The summary of what he says is that the lower-index tensor (without a tilde) is the symbol (again with a tilde) multiplied by the square root of the determinant of the metric: εμ1μ2⋯μn=√|g|˜εμ1μ2⋯μn.
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