Infinitely many solutions for Schrödinger–Maxwell equations with indefinite sign subquadratic potentials

In this paper, we deal with multiplicity of solutions of a class of sublinear Schrödinger–Maxwell equations-Δu+V(x)u+ϕu=f(x,u),inR3,-Δϕ=u2,lim|x|→∞ϕ(x)=0,inR3.Under more relaxed assumptions on V and f, we establish some existence criteria to guarantee that the above problem has at least one or infinitely many nontrivial solutions by using the genus properties in critical theory.