Li, Chong, The study of minimal period estimates for brake orbits of autonomous subquadratic Hamiltonian systems, Acta mathematica Sinica. English series (Print) , 31(10), 2015, pp. 1645-1658
In this paper, we consider the minimal period estimates for brake orbits of autonomous subquadratic Hamiltonian systems. We prove that if the Hamiltonian function H . C 2(R2n,R) is unbounded and not uniformly coercive, there exists at least one nonconstant T-periodic brake orbit (z, T) with minimal period T or T/2 for every number T > 0.