Home / Math and Physics Files / Math / Curvilinear Systems / Tensor Doc and Support / support notes and rejects
app D research
DOCX · 246.0 KB
Open DOCX file
Working notes from the support and rejects folder for Phil's tensor document, concerning conventions for the Levi-Civita tensor E (with a sign factor σ and |g|^-1/2). He derives E contracted with the transformation matrices R as σ|g|^-1/2 times a determinant or Jacobian, then compares it with the results of RLC and Robert Hermann, noting a likely typo in Hermann's power of |g|. The text is fragmentary scratch work.
AI-written summary; may contain errors. This description is approximate.
Extracted text (machine-read; may contain errors)
Appendix D research concerning E conventions
******************************************* scratch work ************************
The upshot of adding σ is that then
Eabc...x R1aR2b.....RNx = σ|g|-1/2 εabc.. R1aR2b.....RNx
= σ |g|-1/2 det(Rij) = σ |g|-1/2 det(∂x'i/∂xk) = σ |g|-1/2 Jinv(x)
so this says then
Eabc...x R1aR2b.....RNx = σ Jinv(x) /
Since the Rij are not tensors, the LHS is not a scalar and neither is the RHS. So I don't see any real value in this equation.
Let's now compare this to RLC and to the translation:
RLC: They define Δ ≡ Jinv/ |g|1/2 so my equation above reads
σΔ(x') = Eabc...x R1aR2b.....RNx
and this agrees with their result except they don't show the σ = ±.
Hermann: uses Δ = J straight, so his result should read
σ |g|-1/2 Δ = Eabc...x R1aR2b.....RNx
but he has the power wrong on |g|, this I think is a typo. Apart from that power, this agrees exactly.
So this builds my confidence a bit that I have the E object defined OK. Interesting that they both got something wrong in this equation, and not the same thing.
Robert Hermann
Here is Hermann's translation (he may be wrong!)
Here is verification of the RL meaning of colon
*****************
εabc... = g εabc...
g
Here is that strange comment again
http://www.scribd.com/doc/55201640/14/The-Levi-Civita-Tensor-and-Hodge-Dualisation
Why is this exception made? OK, see self notes above.