  The dynamical consequences of a bimetric scalar-tensor theory of gravity with
a dynamical light speed are investigated in a cosmological setting. The model
consists of a minimally-coupled self-gravitating scalar field coupled to
ordinary matter fields in the standard way through the metric:
$\metric_{\mu\nu}+B\partial_\mu\phi\partial_\nu\phi$. We show that in a
universe with matter that has a radiation-dominated equation of state, the
model allows solutions with a de Sitter phase that provides sufficient
inflation to solve the horizon and flatness problems. This behaviour is
achieved without the addition of a potential for the scalar field, and is shown
to be largely independent of its introduction. We therefore have a model that
is fundamentally different than the potential-dominated, slowly-rolling scalar
field of the standard models inflationary cosmology. The speed of gravitational
wave propagation is predicted to be significantly different from the speed of
matter waves and photon propagation in the early universe.
