In this paper, we mainly use variational methods, including the least action principle, minimax theorem and Morse theory, to deal with the existence of solutions of discrete Hamiltonian systems with periodic boundary value conditions. This Ph.

• 我们利用变分理论中的最小作用原理、极小极大原理，以及Morse理论研究了离散哈密尔顿系统的周期边值问题。