Existence, Uniqueness, and Parametrization of Lagrangian Invariant Subspaces
Gerhard Freiling, Volker Mehrmann, Hongguo Xu · SIAM Journal on Matrix Analysis and Applications · 2002
The existence, uniqueness, and parametrization of Lagrangian invariant subspaces for Hamiltonian matrices is studied. Necessary and sufficient conditions and a complete parametrization are given. Some necessary and sufficient conditions for the existence of Hermitian solutions of algebraic Riccati equations follow as simple corollaries.