In this paper,we are concerned with the existence of positive ground state solutions for nonlinear critical Kirchhoff type problem and the existence of positive ground state and bound state solutions for a class of critical nonlocal problems of mixed fractional order Laplace operator in exterior domains by using the variational method.The main research content is stated as follows:The first part is devoted to studying the existence of the positive ground state solutions for Kirchhoff type problem where a>0,b>0,4<p<6,and potentials V(x)satisfying suitable assumptions.We estab-lish the existence of the positive ground state solutions by Nehari manifold and concentration-compactness principle.The second part is to study the existence of positive ground state and bound state solutions for critical nonlocal elliptic problem where ? is an exterior domain with RN\? bounded or ? is the whole RN,2<p<2s*,s ?(0,1),2s*=2N/N-2s(N>2s),?>0,and potentials V(x)satisfying suitable assumptions.We prove the existence of ground state solution by Nehari manifold and the global compact-ness Lemma,then the homotopy mapping is constructed by energy estimates and barycenter mapping,and the existence of bound state solution is proved by combining deformation lem-ma. |