On the motion of a rigid body in a Navier-Stokes liquid under the action of a time-periodic force G. GaldiAna Silvestre 35Q3035Q3576D0376D05rigid bodyNavier-Stokes equationsexterior domainperiodic motionsLefschetz fixed point theorem This paper is devoted to the motion of a rigid body in an infinite Navier-Stokes liquid under the action of a time-periodic external force. Assuming that, with respect to an inertial reference frame, the force acts along a fixed direction, we investigate the existence of weak and strong periodic solutions to the equations of the coupled system body-liquid. Indiana University Mathematics Journal 2009 text pdf 10.1512/iumj.2009.58.3758 10.1512/iumj.2009.58.3758 en Indiana Univ. Math. J. 58 (2009) 2805 - 2842 state-of-the-art mathematics http://iumj.org/access/