Hi all,
Could someone explain, please, how the following expression can be written in component notation according to summation convention?
a^{kj};k + G^j_{km} a^{km} + G^k_{km} a^{mj}
it is the case of general tensors (non Cartesian)
indices k, j, m take values 1, 2, 3
G^j_{km} is Christoffel symbol of the second kind
; denotes partial differentiation (it is not covariant differentiation)
The first term is written a^{1j};1 + a^{2j};2 + a^{3j};3
the second is G^j_{11} a^{11} + G^j_{12} a^{12} + G^j_{13} a^{13} + G^j_{21} a^{21} + G^j_{22} a^{22} + G^j_{23} a^{23} + G^j_{31} a^{31} + G^j_{32} a^{32} + G^j_{33} a^{33}
What about the last term? Is k also the summation index, and so \Sum_k \Sum_m G^k_{km} a^{mj} ?
Best regards,
Rudi
Re: Summation convention
G^k_{km} a^{mj}
Is k also the summation index, and so \Sum_k \Sum_m G^k_{km} a^{mj} ?
That's correct. The only free index is j.
So you have
G^1_{11} a^{1j} + G^2_{21} a^{1j} + ...
For some curvlinear systems most of the terms of the Christoffel symbol are zero and the calculation becomes easier.
-- Biswajit
Thanks Biswajit. Regards,
Thanks Biswajit.
Regards,
Rudi