 Rotational constraint correction to sphere mobility

In the preceding two-sphere geometry, holding the second sphere's angular velocity at zero needs a torque $\mathbf{G}=-4\pi \mu a^3{\mathbf{\omega }}_{\infty }$. Its rotlet addsto the first sphere's velocity, in addition to the self-mobility correction from a distant force-free sphere. This leading constraint correction is transverse to the line of centres.