anuttarasammyak's latest activity

The first term has dimension of T^-1 though it should be non dimensional. You should investigate its derivation.

The author explains the figures saying "the point of view of S(or S′)". Therefore, there is a possibility that readers may...

I see. “The moving inertial frame against the original IFR” would eliminate those cases.

I was hoping that the name existed. :( The moving frame can for example rotate and its different points can have different velocities...

I do not think so. In the text, "(absolute) velocity of the moving frame" is better.

An example of my point. Say light is passing on element ##dx^\mu##, i.e., $$ g_{\mu\nu}dx^\mu dx^\nu = 0 $$ After variation of metric $$...

Yes. For $$g_{\mu\nu}= g_{\mu\alpha} g_{\beta\nu} g^{\alpha\beta},\ g^{\mu\alpha} g_{\alpha\nu}=\delta^\mu_\nu...

$$\bar{g}_{\mu\nu} - g_{\mu\nu} = \delta g _{\mu\nu} = - \delta \bar{g}_{\mu\nu} $$ ##\bar{g}_{\mu\nu}## is a tensor in the world where...

I agree that index raise- lower operation should be done using one same, old or new, metric for all the indexes of all the entities in...

My bad. I withdraw it.

To me the point is two metrics: original and varied. In varied metric world what kind of things or relations remain and what does not ?

Thanks. I will restate it to confirm my understanding. Here I try not to refer controversial (at least to me) tensor and concentrate on...

First of all, thanks @JimWhoKnew So in general cases which could include ##\delta g^{\mu\nu}##, do we need further information or...

I am sorry I don't understand "the same signature". If A is g itself, I think that B = A = g. A=mg, B=1/m g where m is a real number...

Going back to basics, Dirac's textbook defines a tensor as follows: $$...