Constraints on generalized extended inflationary models

We study the physical constraints on generalized extended inflationary theories, in which the Brans-Dicke field $\Phi$ couples to the inflaton sector in the form of two arbitrary power-law functions of $\Phi$. We find that the most stringent constraints arise from the need to suppress large bubbles and from considerations of the density perturbations generated during extended inflation. We find that there are sizable portions of the parameter spaces in which all the constraints are satisfied.