Entire Solutions for a Class of Fourth-Order Semilinear Elliptic Equations with Weights

We investigate the problem of entire solutions for a class of fourth-order, dilation invariant, semilinear elliptic equations with power-type weights and with subcritical or critical growth in the nonlinear term. These equations define noncompact variational problems and are characterized by the presence of a term containing lower order derivatives, whose strength is ruled by a parameter lambda. We can prove existence of entire solutions found as extremal functions for some Rellich-Sobolev type inequalities. Moreover, when the nonlinearity is suitably close to the critical one and the parameter lambda is large, symmetry breaking phenomena occur and in some cases the asymptotic behavior of radial and nonradial ground states can be somehow described.