GITA: A REDUCE program for the normalization of polynomial Hamiltonians Original Research Article

For a given polynomial Hamiltonian near an equilibrium point the program GITA calculates analytically the normal Birkhoff-Gustavson form in Cartesian as well as angle-action coordinates and the formal integral of the motion. These quantities are presented in the form of a truncated power series, the highest degree of which determines the degree of the approximation. The program performs the calculation of the modified normal Birkhoff-Gustavson form for the Hamiltonian restricted by the resonance condition. The program package is written in the computer algebra system REDUCE.