We develop subrepresentation inequalities for infinitely degenerate metrics, and obtain corresponding Poincare and Sobolev inequalities. We then derive conditions on the degenerate metric under which weak solutions to associated infinitely degenerate equations with rough coefficients are locally bounded, satisfy a maximum principle, or are continuous. As an application we obtain W-hypoellipticity of certain infinitely degenerate quasilinear equations with smooth coefficients having mild nonlinearities and degeneracies.
Comment: 185 pages. Proof of Sobolev inequality fixed, changed back to the correct proof in earlier versions. The radius r on the right hand side of Sobolev inequality is replaced by a different quantity called superradius. This version is submitted for publication