A Dirac's "GTR" Eq (27.4): how momentum ##p^\mu## varies

[Kostik]

I just noticed that Dirac actually derives the Lie derivative in chapter 30, on page 60. Here he calculates the variation $\delta g_{\mu\nu} = -\mathcal{L}_b \, g_{\mu\nu}$ in order to make the reverse argument that I provided in Post #34. There, to calculate the $\delta p^\mu$ in Dirac's (27.4), I took a point transformation and considered it as a coordinate transformation. In chapter 30, Dirac has a coordinate transformation, derives the Lie derivative $-\mathcal{L}_b \, g_{\mu\nu}$, and then considers it as a point transformation in order to find $\delta g_{\mu\nu}$.

The odd thing is, since he does this is chapter 30, he could have done it in chapter 27 to give a solid proof of (27.4).