  Close to the chiral limit, many calculations in numerical lattice QCD can
potentially be accelerated using low-mode deflation techniques. In this paper
it is shown that the recently introduced domain-decomposed deflation subspaces
can be propagated along the field trajectories generated by the Hybrid Monte
Carlo (HMC) algorithm with a modest effort. The quark forces that drive the
simulation may then be computed using a deflation-accelerated solver for the
lattice Dirac equation. As a consequence, the computer time required for the
simulations is significantly reduced and an improved scaling behaviour of the
simulation algorithm with respect to the quark mass is achieved.
