We consider classical and quantum dynamics of a free particle in de Sitter's
space-times with different topologies to see what happens to space-time
singularities of removable type in quantum theory. We find analytic solution of
the classical dynamics. The quantum dynamics is solved by finding an
essentially self-adjoint representation of the algebra of observables
integrable to the unitary representations of the symmetry group of each
considered gravitational system. The dynamics of a massless particle is
obtained in the zero-mass limit of the massive case. Our results indicate that
taking account of global properties of space-time enables quantization of
particle dynamics in all considered cases.Comment: Class. Quantum Grav. 20 (2003) 2491-2507; no figures, RevTeX