Topology of billiard problems, II
  We give topological lower bounds on the number of periodic and closed trajectories in strictly convex smooth billiards. We use variational reduction admitting a finite group of symmetries and apply topological approach based on equivariant Morse and Lusternik - Schnirelman theories.   The paper continues results published in math.DG/9911226 and math.DG/0006049 
Michael Farber