[GiNaC-list] Ordering and pattern matching

[Vladimir V. Kisil]

		Hi, Chris,

>>>>> On Tue, 25 Aug 2009 16:12:37 +0100, Chris Kelly <giltirn at gmail.com> said:

    CK> grips with the clifford algebra classes. I am trying to perform
    CK> the simple substitution: 
    CK> A_mu gamma_mu B_nu gamma_nu = A_mu A_nu delta_mu,nu (Euclidean space).

	Why you are doing this replacement? I do not think it is mathematically
  correct, it shall be:

A_mu gamma_mu B_nu gamma_nu + B_nu gamma_nu A_mu gamma_mu  = A_mu A_nu delta_mu,nu  

  You can get that answer by canonicalize_clifford() method without any
  substitution. 

    CK> Here is some example code:

    CK>   ex metric = unit_matrix(4); idx i(symbol("i"),4) ,
    CK>   j(symbol("j"),4); ex al_i = clifford_unit(i,metric); //Use
    CK>   //  generalised clifford gamma  matrices for euclidean space
    CK>   //Create generic 'slashed' symbols with euclidean metric

	You may prefer to use delta tensor rather than unit matrices to
  create this Clifford units---output of simplification will be more
  transparent. 

  Best wishes,
  Vladimir
-- 
Vladimir V. Kisil     email: kisilv at maths.leeds.ac.uk
--                      www: http://maths.leeds.ac.uk/~kisilv/