Recent content by Torg

I am happy you wrote a book. I think it will be an excellent and very useful book. Congratulations! Does the book discuss tensor analysis, or could i read the contents?

It is very well explained except the paragraph "We will not delve into definitions of energy in general relativity such as the hamiltonian (amusingly, the energy of a closed universe always works out to zero according to this definition), various kinds of energy one hopes to obtain by...

I quote "no good way of defining global energy conservation", why is that?

Edit: Note that in the term on the form \[\begin{array}{l} {\Gamma _{..}}^{.}{T_{..}} \\ \end{array}\] there is no way to place indices such that there is only one free covariant index left, since there are 4 covariant and only one contravariant index and the left-hand side has only one free...

Thank you very much. What about non conserved Energy-momentum in General Relativity because the energy of the gravitational filed in not included in it, and that gravity can be removed locally "free fall"?

Dr. Stavros Kiri helped me with this ebook [PDF]http://elisa.ugm.ac.id/user/archive/download/66514/b818578e2246cb5c10d3547197b62209 the author used the wrong expression as i did in page (53) equation (21.20). I think my lecturer at our department is using that reference.

I thought the metric goes immediately to work into the tensor indices to give a mixed tensor not to the differentiation index itself. I am learning a lot. Thank you very much Orodruin.

Sorry, there a little mistake in the second expression. The first term in the RHS should be the ordinary partial derivative instead of the covariant derivative.

Thank you all again. I will ask for much today :-) I would like to know name of a good reference in introductory Differential Geometry. I struggled whole night with the second expression below, I couldn't figure out the positions of the indices \[\begin{array}{l} {T^{ab}}_{;b} =...

I understand it now. Thank you all very much for the help. You have been excellent in explaining it.

I have to checked that if it doesn't affect the Bianchi second identity.

I got it, but I will take it with a grain of salt.

I am really sad! to give up using EFEs in their covariant form when it comes to apply the conservation of energymomentum tensor.

Why do I need to contact it? when i use EFEs in their covariant form and when I differentiate both sides covariantly and put the divergence of the energymomentum tensor equals to zero the left hand side should give the same set of equation of motion.

shall i just forget about it? I use the lower expression a lot.