Existence And Multiplicity Results Of Some Nonlinear Biharmonic Equations

In this paper, the usual notions of superlinearity and sublinearity for Biharnionic problems A2u cAu=f(x,u) are given a local form and extended to infinite nonlinearities. Here f(x,s) is allowed to change sign or to vanish for s near zero as well as for s near infinity.In chapter one, we present some basic definitions, notations and facts that will be used later in this paper. At the same time, we outline some fundamental results of some nonlinear elliptic equations.In chapter two, we prove the existence and multiplicity results of some nonlinear biharmonic equations by using lower scmicontinuity method and minimax method.