Complement preserving operators (Q1893268)

The authors study linear operators \(T\) on real inner product spaces, usually of finite dimension which preserve orthogonal complements in the sense that the orthogonal complement of any invariant subspace is invariant. They prove for instance that the space can be split into mutually orthogonal subspaces such that \(T\) is symmetric on one subspace and strictly complex (with no real eigenvalues) on the others.