Recent content by nenyan

Summary: different methods give different results. They are not consistent. Summary: different methods give different results. They are not consistent. I use two different methods to detect whether a matrix is singular. The result of calculating the determinant of a 9-order square matrix is...

Thank you very much.

Thank you!

How to find some papers on Lorentz invariant extensioning of standard electromagnetism that include magnetic charges

Thank you! I see.

I am reading GEOMETRY, TOPOLOGY AND PHYSICS written by MIKIO NAKAHARA (second edition). I have a problem on page 400. I wonder why the sign is minus in Eq. (10.85). And the same problem appears on page 405 in Eq.(10.108). I think it should be minus one half.

Oh, I see. Thank you very much, fzero.

Thank you fzero! Could you please give me some detail? How to get $$ \partial_i\partial_j \hat{h}^r_{ij} + 2 \partial^4 \epsilon = 2 \partial^2\alpha.$$ from $$\delta\hat{h}^r_{ii} + 2 \partial^2 \epsilon = 6 \alpha,$$ And how to get the frist line of (A.5). Actually, I do not understand the...

Is there anyone can give me a hand? http://arxiv.org/abs/astro-ph/0210603 When I read this paper I can not get Eq.(A.5) from (A.4). Why it is ##4\alpha##? If we take the trace of Eq.(A.4), why not it give us ##6\alpha##? Eq. (A.3): [Edited by a mentor to fix a small problem in the Latex...

Thank you. I see. Kij=gimgjnKmn I should consider another Kij here.

I got the result that is consist with references in fisrt case. Is there anything wrong in 2nd way?

Yes. It's the transformation from x to x'. δ is Variational symbol.

Homework Statement δ (∂x'^μ/∂x^β)=0 This equation is on my textbook. I don't quite understand. Where x'^μ is coordinate component. Homework Equations The Attempt at a Solution

Thank you Peter. I kind of understand...

Could you please explain it in detail? Why I run into problems? What is field strength? In my opinion, it is a parameter to describe a property of the field. The property is belong to the field, it is the nature feature of the field. dF/dQ is determined by the EM filed itself and has nothing...