  The geometric intrinsic approach to Hojman symmetry is developed and use is
made of the theory of the Jacobi last multipliers to find the corresponding
conserved quantity for non divergence-free vector fields. The particular cases
of autonomous Lagrangian and Hamiltonian systems are studied as well as the
generalization of these results to normalizer vector fields of the dynamics.
The nonautonomous cases, where normalizer vector fields play a relevant role,
are also developed.
