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## Main Question or Discussion Point

hello

For the same Friedmann metric, Landau (Classical theory of fields) finds a value for the Riemann curvature scalar which is given in section 107 :

R = 6/a

whereas in MTW , in box 14.5 , equation 6 , its value is :

R = 6(a

The metric is the same ! how come ? this could not be related to the fact that Landau does the replacement :

cd[itex]\tau[/itex] = ad[itex]\eta[/itex]

For the same Friedmann metric, Landau (Classical theory of fields) finds a value for the Riemann curvature scalar which is given in section 107 :

R = 6/a

^{3}( a + d^{2}(a)/dt^{2})whereas in MTW , in box 14.5 , equation 6 , its value is :

R = 6(a

^{-1}d^{2}(a)/dt^{2}+ a^{-2}(1 + (d(a)/dt)^{2}) )The metric is the same ! how come ? this could not be related to the fact that Landau does the replacement :

cd[itex]\tau[/itex] = ad[itex]\eta[/itex]