[GiNaC-list] question about lorentz_g contract with sy_anti tensor

[Vladimir V. Kisil]

>>>>> On Sun, 26 May 2019 09:45:27 +0000, Feng Feng <F.Feng at outlook.com> said:
    FF> So if I want to contract two index in A, I mean, we need this
    FF> one: A^{abc}_{c} = A^{abcd} * g^{dc} ?

    No, you need A^{abc}_{c} = A^{abcd} * g_{dc}. To have a dummy summation
  over varidx you need its two instances with different variance.

-- 
Vladimir V. Kisil                 http://www.maths.leeds.ac.uk/~kisilv/
  Book:     Geometry of Mobius Transformations     http://goo.gl/EaG2Vu
  Software: Geometry of cycles          http://moebinv.sourceforge.net/