A note on the geometry of linear Hamiltonian systems of signature 0 in R^4
arXiv:math/0510352
Abstract
It is shown that a linear Hamiltonian system of signature zero in 4 dimensions is elliptic or hyperbolic according to the number of Lagrangian planes in the null-cone , or equivalently the number of invariant Lagrangian planes. An extension to higher dimensions is described.
arXiv comment7 pages