## How Many Parameters are There in the Friedmann Model of the Universe?

Friedmann, "On the curvature of space" (1922) and "On the possibility of a world with constant negative curvature" (1924), chose a hyperbolic line element in which the spatial part was the hemisphere model equipped with a Riemann metric. There were two unknown parameters, R^{2} and M ^{2}, that multiplied the space and time components of the metric, respectively, and were required to satisfy the Einstein field equations.