  Known millisecond pulsars have periods longer than 1.558 ms. Recycled in
binary systems, neutron stars can attain very short spin periods. In this paper
we investigate the expected properties of the millisecond pulsar distribution
by simulating synthetic populations under different assumptions for the neutron
star equation of state and decay of the magnetic field. We find evidence that a
tail in the distribution of millisecond pulsars may exist at periods shorter
than those observed.
