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Printing mistake in A First Course in General Relativity?

  1. Apr 9, 2010 #1
    Is is a typo? The 1985 edition of Schutz: A First Course in General Relativity, p. 52, equation 2.37, which is supposed to express the idea that "photons have spatial momentum equal to their energy":

    [tex]\vec{p} \cdot \vec{p} = -E^2 + E^2 = 0.[/tex]

    Shouldn't this be

    [tex]\vec{p} \cdot \vec{p} = E^2[/tex]


    [tex]E^2 - \vec{p} \cdot \vec{p} = 0?[/tex]
  2. jcsd
  3. Apr 9, 2010 #2
    Oh, sorry, my mistake. I just realised--seconds after posting this!--that he's using the symbol [itex]\vec{p}[/itex] for the energy-momentum 4-vector, rather than for spatial momentum.
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