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Question on general principle of relativity

  1. Feb 11, 2009 #1
    I want to ask about the two statements.
    1) Physics laws remain unchange at any Gauss' coordinates.
    2) Physical laws are the same in all reference frames -- inertial or non-inertial.

    Why is 1st statement better than the second statement in representing the general principle of relativity?

    What's the importance of including the Gauss; coordinates?

    I know this may be simple question but i am really struggling about it.
  2. jcsd
  3. Feb 11, 2009 #2


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    Welcome to PF!

    Hi Ronald_Ku! Welcome to PF! :smile:
    Well, I think the 2nd statement is better …

    Gaussian coordinates (synchronous coordinates) aren't covariant.

    (see http://en.wikipedia.org/wiki/Coordinate_conditions#Synchronous_coordinates)
  4. Feb 11, 2009 #3
    The first one is a bit more mathematical and the second one is a bit more intuitive or physical.

    Do you have a reason to think the first statement is "better" than the second?
  5. Feb 12, 2009 #4
    Well, I found the 1st statement better from the book " Relativity: The Special and the General Theory".
  6. Feb 12, 2009 #5


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    Einstein's book?

    ah … you mean Einstein's book?

    Einstein wrote the book a long time ago, when "Gaussian coordinates" had a different meaning.

    Then, they meant any curvilinear coordinates, now they mean synchronous coordinates.

    I assumed you meant synchronous coordinates.

    If they mean any coordinates, I don't see much difference between the statements, except that, as altonhare :smile: says, the first is slightly more mathematically expressed.

    Are you using Lawson's English translation in the 2002 http://books.google.com/books?id=f_...lativity:+The+Special+and+the+General+Theory"? If so, which page is it on?
    Last edited by a moderator: Apr 24, 2017
  7. Feb 12, 2009 #6
    No I'm a chinese. I'm using the edition translated to chinese.
    I just translate all the words I read to english.
    Besides I still don't see what you mean.
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