[GiNaC-list] Tricky way to control over dummy indices

Vladimir V. Kisil kisilv at maths.leeds.ac.uk
Fri Jul 14 21:04:15 CEST 2017


>>>>> On Fri, 14 Jul 2017 22:54:35 +0430, esarcush esarcush <esarcush at gmail.com> said:

    EE> Dear all, in expression

    EE> { indexed(A, i, j) * indexed(B, j, k) }

    EE> GiNaC is saying that the dummy index is "j" and "i, k" are
    EE> free. Is there a way to determine dummy indices based on
    EE> Einstein summation notation; namely all the indices in the
    EE> latter be free.

  My understanding of

https://en.wikipedia.org/wiki/Einstein_notation

  is that in the above expression there is summation over j, thus it is
  not free.
-- 
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/


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