Chinese Scholar Yang Jian liang Putting Wrongs to Rights in Astrophysics

[NotEinstein]

I recommend you a few of basic textbooks to help you study: R.J. Adler, M. Schuffer " Introduction to General Relativity" 1965, New York,

And I recommend you another textbook: "An Introduction to Modern Astrophysics" (2nd edition), by Carroll. It's a bit more up-to-date.

Edit: But let's look at your source anyway, since I happen to have it right in front of me (2nd edition). On page 52, equation 2.10, a notation is introduced: the curly-bracket-thing is minus the Christoffel symbol. On page 169, the contracted Ricci tensor is given in equation 5.118. If you substitute equation 2.10, you'll find out that Adler, Bazin, and Schiffer derive the same result as Carroll and the Wikipedia-page.

Your own source proves that I was right all along, and Yang is a minus-sign off!

 

[heyuhua]

And I recommend you another textbook: "An Introduction to Modern Astrophysics" (2nd edition), by Carroll. It's a bit more up-to-date.

Edit: But let's look at your source anyway, since I happen to have it right in front of me (2nd edition). On page 52, equation 2.10, a notation is introduced: the curly-bracket-thing is minus the Christoffel symbol. On page 169, the contracted Ricci tensor is given in equation 5.118. If you substitute equation 2.10, you'll find out that Adler, Bazin, and Schiffer derive the same result as Carroll and the Wikipedia-page.

Your own source proves that I was right all along, and Yang is a minus-sign off!

in GR' equations there is indeed sign difference in different textbooks, this is because diffierent authors may use diffierent definition about Minkovsky metric, as long as notice calculation in different set they are all reght, don't mean error

 

[NotEinstein]

in GR' equations there is indeed sign difference in different textbooks, this is because diffierent authors may use diffierent definition about Minkovsky metric, as long as notice calculation in different set they are all reght, don't mean error

I just explained to you: the book you brought up has no sign difference with Carroll or Wikipedia; it agree with them completely. It does have a sign difference in the contracted Ricci calculation when compared to Yang; thus, Yang is wrong, according to the textbook you brought up!

I don't get how you can misunderstand your own source so badly; it's quite pathetic, to be honest.

 

[heyuhua]

for example, in some books gravitational field equation reads G^uv=-8paiGT^uv, but in other books it is writen as G^uv=8paiGT^uv, both they are right, why to raise two writings comes from different definitions about Minkovsky metric. Of course, in Yang's articles the field equation is writen as G^uv=4paiGT^uv and in the same time pressure P takes negative , which is a great modification to G^uv=-8paiGT^uv, Yang's work value is here.

 

[NotEinstein]

for example, in some books gravitational field equation reads G^uv=-8paiGT^uv, but in other books it is writen as G^uv=8paiGT^uv, both they are right, why to raise two writings comes from different definitions about Minkovsky metric. Of course, in Yang's articles the field equation is writen as G^uv=4paiGT^uv and in the same time pressure P takes negative , which is a great modification to G^uv=-8paiGT^uv, Yang's work value is here.

Find me even a single source where there's such a minus-sign difference due to conventions in the contracted Ricci tensor calculation. You know, the equation we've been talking about for over a hundred posts now.

And if the minus-sign in the Yang's EFE is due to conventions... Yang clearly directly compares the newly derived $$4\pi G$$ with the $$-8\pi G$$, indicating Yang is convinced this is a real difference, not something due to a minus-sign convention. Congratulations, you've just utterly and completely destroyed Yang's work!

 

[heyuhua]

Find me even a single source where there's such a minus-sign difference due to conventions in the contracted Ricci tensor calculation. You know, the equation we've been talking about for over a hundred posts now.

And if the minus-sign in the Yang's EFE is due to conventions... Yang clearly directly compares the newly derived $$4\pi G$$ with the $$-8\pi G$$, indicating Yang is convinced this is a real difference, not something due to a minus-sign convention. Congratulations, you've just utterly and completely destroyed Yang's work!

Find me even a single source where there's such a minus-sign difference due to conventions in the contracted Ricci tensor calculation. You know, the equation we've been talking about for over a hundred posts now.

And if the minus-sign in the Yang's EFE is due to conventions... Yang clearly directly compares the newly derived $$4\pi G$$ with the $$-8\pi G$$, indicating Yang is convinced this is a real difference, not something due to a minus-sign convention. Congratulations, you've just utterly and completely destroyed Yang's work!

this means neither do you understand Yang nor do understand me, it ' s best to wait until you understand and then put out your comments , to comment indiscriminately is to poop on other people's articles and to insult authors and mislead the public

 

[arfa brane]

this means neither do you understand Yang nor do understand me, it ' s best to wait until you understand and then put out your comments , to make a random comment is to mislead people

That's quite a claim. But I expect a lot of people don't understand Yang or you. As far as I can see it, this thread has been about you defending what a lot of people call a mistake. If it isn't a mistake you should explain why it isn't and how Yang's reasoning leads to his result.

If it's revolutionary, why isn't it being cited or talked about? Coming to this forum with Yang's revolutionary idea isn't a great look for it, this isn't much of a hub of scientific thinking shall we say, why not sling it at physorg?

 

[wangchaoqing]

in fact , your questions have already been answer by Heyuhua some times, howerer you don't see or turn a blind eye

 

[NotEinstein]

this means neither do you understand Yang nor do understand me,

You've had over a hundred posts time to explain yourself, and all you did was shoot yourself in the foot, with the Adler et al textbook disproving your point, with you contradiction Yang directly, etc. It seems that when it comes to understanding, I'm lightyears ahead of you!

it ' s best to wait until you understand and then put out your comments ,

Let me explain. This website is an internet discussion forum, focused mainly on science. People come here to discuss science. You posted Yang's work here. I'm trying to discuss it, but you don't seem to be willing to do that. Waiting for somebody to understand it is exactly what this forum is not about. If you didn't want to explain or discuss Yang's work, you shouldn't have come here.

to comment indiscriminately

Which is not something that I've done.

is to poop on other people's articles

Have you ever heard of "peer review"? If Yang wants to get his/her work published (i.e. get noticed by the scientific community), hundreds of people will have to "poop" onto his work.

and to insult authors

If I have done so, I apologize. However, you have insulted me in this very thread. If you think insults are bad, what does that tell you about your own behavior?

and mislead the public

Well, let's look at that. You join this forum, and post Yang's work. Some questions are raised, and you cannot answer them. A minus-sign difference is found, and you cannot address it. In fact, you post material (the Adler et al textbook) pretending that it supports Yang, while in reality it disproves Yang! That is misleading. Conclusion: one of us has been "misleading the public", but it isn't me.

in fact , your questions have already been answer by Heyuhua some times, howerer you don't see or turn a blind eye

Perhaps you can explain it to me then, because according to you I can't understand heyuhua's answers. In his work, Yang introduces a minus-sign difference in the contracted Ricci tensor definition when compared to a Wikipedia-author, Carroll, and the Adler et al textbook. Carroll uses the same sign-convention for the metric Yang does (haven't checked the others). Yang compares the obtained EFE directly with the ones Wikipedia, Carroll, and Adler et al get, meaning all the terms in the equation must have the same meaning (i.e. no minus-sign differences that change the meaning of the equation).

How is it possible that Yang's derivation is correct?

 

[heyuhua]

in fact , your questions have already been answer by Heyuhua some times, howerer you don't see or turn a blind eye

I think that either NotEinstin is an idiot or he Intentionally make trouble

 

[NotEinstein]

I think that either NotEinstin is an idiot or he Intentionally make trouble

See, another insult aimed at me! How about you actually answer questions instead?

 

[heyuhua]

You've had over a hundred posts time to explain yourself, and all you did was shoot yourself in the foot, with the Adler et al textbook disproving your point, with you contradiction Yang directly, etc. It seems that when it comes to understanding, I'm lightyears ahead of you!


Let me explain. This website is an internet discussion forum, focused mainly on science. People come here to discuss science. You posted Yang's work here. I'm trying to discuss it, but you don't seem to be willing to do that. Waiting for somebody to understand it is exactly what this forum is not about. If you didn't want to explain or discuss Yang's work, you shouldn't have come here.


Which is not something that I've done.


Have you ever heard of "peer review"? If Yang wants to get his/her work published (i.e. get noticed by the scientific community), hundreds of people will have to "poop" onto his work.


If I have done so, I apologize. However, you have insulted me in this very thread. If you think insults are bad, what does that tell you about your own behavior?


Well, let's look at that. You join this forum, and post Yang's work. Some questions are raised, and you cannot answer them. A minus-sign difference is found, and you cannot address it. In fact, you post material (the Adler et al textbook) pretending that it supports Yang, while in reality it disproves Yang! That is misleading. Conclusion: one of us has been "misleading the public", but it isn't me.


Perhaps you can explain it to me then, because according to you I can't understand heyuhua's answers. In his work, Yang introduces a minus-sign difference in the contracted Ricci tensor definition when compared to a Wikipedia-author, Carroll, and the Adler et al textbook. Carroll uses the same sign-convention for the metric Yang does (haven't checked the others). Yang compares the obtained EFE directly with the ones Wikipedia, Carroll, and Adler et al get, meaning all the terms in the equation must have the same meaning (i.e. no minus-sign differences that change the meaning of the equation).

How is it possible that Yang's derivation is correct?

I didn't read Carroll's book and didn't know how he define Ricci sensor, but in a lot of textbook the definition is like the form in Yang's article, that is to say, the minus sign is correct and isn't a mistake at all

 

[heyuhua]

You've had over a hundred posts time to explain yourself, and all you did was shoot yourself in the foot, with the Adler et al textbook disproving your point, with you contradiction Yang directly, etc. It seems that when it comes to understanding, I'm lightyears ahead of you!


Let me explain. This website is an internet discussion forum, focused mainly on science. People come here to discuss science. You posted Yang's work here. I'm trying to discuss it, but you don't seem to be willing to do that. Waiting for somebody to understand it is exactly what this forum is not about. If you didn't want to explain or discuss Yang's work, you shouldn't have come here.


Which is not something that I've done.


Have you ever heard of "peer review"? If Yang wants to get his/her work published (i.e. get noticed by the scientific community), hundreds of people will have to "poop" onto his work.


If I have done so, I apologize. However, you have insulted me in this very thread. If you think insults are bad, what does that tell you about your own behavior?


Well, let's look at that. You join this forum, and post Yang's work. Some questions are raised, and you cannot answer them. A minus-sign difference is found, and you cannot address it. In fact, you post material (the Adler et al textbook) pretending that it supports Yang, while in reality it disproves Yang! That is misleading. Conclusion: one of us has been "misleading the public", but it isn't me.


Perhaps you can explain it to me then, because according to you I can't understand heyuhua's answers. In his work, Yang introduces a minus-sign difference in the contracted Ricci tensor definition when compared to a Wikipedia-author, Carroll, and the Adler et al textbook. Carroll uses the same sign-convention for the metric Yang does (haven't checked the others). Yang compares the obtained EFE directly with the ones Wikipedia, Carroll, and Adler et al get, meaning all the terms in the equation must have the same meaning (i.e. no minus-sign differences that change the meaning of the equation).

How is it possible that Yang's derivation is correct?

I didn't read Carroll's book and didn't know how he define Ricci sensor, but in a lot of textbook the definition is like the form in Yang's article, that is to say, the minus sign is correct and isn't a mistake at all. note that in the contracted Ricci tensor up-down repeated indicators represent summation

 

[NotEinstein]

I didn't read Carroll's book and didn't know how he define Ricci sensor, but in a lot of textbook the definition is like the form in Yang's article, that is to say, the minus sign is correct and isn't a mistake at all.

You are right in that Carroll uses the same form for the Ricci tensor. Which is why Yang's minus-sign in the contracted Ricci tensor is thus obviously a mistake!

note that in the contracted Ricci tensor repeated up-down repeated indicators represent summation

Yes, I am familiar with Einstein summation. As is Carroll, that Wikipedia-author, and Adler et al. But even if I wasn't, I would still be able to comparing to equations and spot that minus-sign mistake; Einstein summation has nothing to do with that.​

 

[heyuhua]

Yang's minus-sign in the contracted Ricci tensor comes from the definition of Ricci tensor, how can the mistake rise ? please you write here full Ricci tensor, let me see what your definition of Ricci tensor is

 

[NotEinstein]

Yang's minus-sign in the contracted Ricci tensor comes from the definition of Ricci tensor, how can the mistake rise ? please you write here full Ricci tensor, let me see what your definition of Ricci tensor is

I've already given it multiple times, but here's a nice convenient list because apparently you've forgotten:
Carroll, equation 3.114, page 129.
Adler et al, equation 5.117', page 169.
Wikipedia: https://en.wikipedia.org/wiki/List_of_formulas_in_Riemannian_geometry#Ricci_and_scalar_curvatures

 

[heyuhua]

here definition of Ricci tensor is the same as Yang's article, there is the same minus sign, too. when it is linearized its back two terms are neglected

 

[NotEinstein]

here definition of Ricci tensor is the same as Yang's article, there is the same minus sign, too.

It's right in front of you: the terms in Yang's article both carry a different sign.

 

[heyuhua]

I look seriously through the chapter and find that your question is still the definition's question, indeed in some book, for example Carroll's book , the Ricci tensor is defined as R^uviuj, in other book defined as R^uviju, different contracted index, thus there exist the sign difference, inYang's article use the form R^uviju

 

[heyuhua]

when use the form R^uviuj field equation read G^uv=8paiGT^uv, when use the form R^uviju field equation read G^uv= - 8paiGT^uv, both they are correct