A vector space over a field is symplectic if it is equipped with an exterior 2-form such that has the maximal rank.
A subspace in a symplectic vector space is isotropic if for all and Lagrangean (or lagrangian) if it is maximal isotropic (not proper subspace in any isotropic subspace). See wikipedia.
| type of subspace of inner product space | condition on orthogonal space | |
|---|---|---|
| isotropic subspace | ||
| coisotropic subspace | ||
| Lagrangian subspace | (for symplectic form) | |
| symplectic space | (for symplectic form) |