/freed"meuhn/ , Astron.
any model of the universe deduced from a homogeneous, isotropic solution of Einstein's field equations without a cosmological constant. Such models form the mathematical basis for many modern cosmologies and provide for expansion or contraction of the universe. Also called Friedmann universe .
[ named after Alexander Friedmann, (1885-1925), Russian mathematician, who made the necessary calculations in 1922 ]