Gauss-Bonnet Inflation
  We consider an Einstein-Scalar-Gauss-Bonnet gravitational theory, and argue
that at early times the Ricci scalar can be safely ignored. We then demonstrate
that the pure scalar-Gauss-Bonnet theory, with a quadratic coupling function,
naturally supports inflationary -- de Sitter -- solutions. During inflation,
the scalar field decays exponentially and its effective potential remains
always bounded. The theory contains also solutions where these de Sitter phases
possess a natural exit mechanism and are replaced by linearly expanding --
Milne -- phases.
