I'm trying to learn some facts concerning symplectic spaces and I have found this affirmation I cannot prove:
If $x$ is self adjoint in a symplectic vector space then there's an isotropic flag $V_1\subset V_2\subset \cdots\subset V_n$ stable by $x$.
Here $2n$ is the dimension of the vector space.
I hope someone can give me a hint. Thank you very much.
