Discrete Hamiltonian Systems

This text explores several aspects of discrete Hamiltonian systems. It provides interconnections between symplectic systems, recessive and dominant solutions, various discrete Riccati equations, and continued fraction representations of solutions of Riccati equations. It also covers variable step size discrete variational theory, a discrete Legendre transformation from discrete Euler-Lagrange equations to discrete Hamiltonian systems. Use is made of the implicit function theorem to show the importance of step size in numerical solutions of Hamiltonian systems. An "a priori" step size criterion shows how one can avoid parasitic numerical solutions.