Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Einstein Notation

  1. Apr 11, 2010 #1
    I thought that when you used a roman letter such as v that you started at 1 instead of 0. For instance if you had:
    [tex] A^v C_{\mu v} [/tex]

    Wouldn't that just be: [tex] A^1C_{\mu 1} + A^2C_{\mu 2} + A^3C_{\mu 3} [/tex] ?

    (this is one of the problems with a solution from Schutz's book and the solution starts with [tex] v = 0 [/tex] )
  2. jcsd
  3. Apr 11, 2010 #2


    User Avatar
    Homework Helper
    Gold Member

    Are you sure its not a [tex] \nu [/tex] instead of a [tex] v [/tex]?
  4. Apr 11, 2010 #3


    User Avatar
    Gold Member

    I think in many notations the index normally represents a 4-vector(though it doesn't HAVE to be 4 dimensions), which in some(most?) notations start with 0. Any pairs of indices just implies a sum. I think for everything I've ever done the first index is 0 rather than 1.
  5. Apr 11, 2010 #4
    Wow! Thanks for pointing that out - the two are confusingly similar in appearance :biggrin:.
  6. Apr 11, 2010 #5
    Usually Latin indicies start i,j,k ... if the author has indicated a different convention between Latin and Greek indecies.
  7. Apr 11, 2010 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    A lot of older books use the convention that Latin versus Greek indices indicates spacelike indices versus ones that range over all four dimensions. The convention you'll see more commonly in newer books is to use abstract index notation http://en.wikipedia.org/wiki/Abstract_index_notation , with Latin indices indicating that they're abstract indices, Greek meaning that they refer to a particular basis.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook