The conformal transformation on a space with parallel Ricci tensor.

A gas turbine power plant has a compressor stage and a turbine stage with an annular combustion stage therebetween. Each of the contra-rotatable compressor rotors is connected to one of the contra-rotatable turbine rotors by an elongated hollow cylindrical shaft concentric with an axially extending fixed shaft to form an integral unit. The units are operably connected by differential gearing mounted on the fixed shaft just in rear of the nose of the engine at the air intake end of the housing.