We study the Einstein-Vlasov system coupled to a nonlinear scalar field with
a nonnegative potential in locally spatially homogeneous spacetime, as an
expanding cosmological model. It is shown that solutions of this system exist
globally in time. When the potential of the scalar field is of an exponential
form, the cosmological model corresponds to accelerated expansion. The
Einstein-Vlasov system coupled to a nonlinear scalar field whose potential is
of an exponential form shows the causal geodesic completeness of the spacetime
towards the future. The asymptotic behaviour of solutions of this system in the
future time is analysed in various aspects, which shows power-law expansion.Comment: 30 page