= Solution
A nonrotating <elliptical galaxy> need not have an isotropic <velocity ellipsoid>: unequal random-motion stresses in different directions can support an oblate or triaxial shape without substantial mean rotation. The <tensor virial theorem>, $2T_{ij}+W_{ij}=0$ for a stationary isolated system with appropriate boundary terms, balances this directional kinetic stress against the directional gravitational stress. \b[Anisotropic random motions can supply the flattening], whereas an isotropic nonrotating equilibrium has much stronger restrictions on its shape.
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