If we ignore the spatial variables, the phase space of a gas with three particles is three dimensional, which permits one to sketch the n -spheres over which the integral over phase space must be taken. If all three particles are together, the split between the two gases is 3|0. Accessible phase space is delimited by an ordinary sphere (2-sphere) with a radius that is either 2 E 1 or 2 E 2 (depending which system has the particles).