Existence of solutions for fractional Klein–Gordon–Maxwell equations involving Hardy–Sobolev critical exponents

This paper is dedicated to investigating the existence of solutions for fractional Klein–Gordon–Maxwell equations involving Hardy–Sobolev critical exponents. By means of the Mountain Pass Theorem, infinitely many critical points and the least energy solution with positive energy for the subcritical system are obtained. Then we prove that there are at least two different solutions for the critical system by the Ekeland variational principle.