2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60364Let $Ω$ be a non-singular syplectic form on some vector space $V$. Denote by $S^{n}_{k}(Ω)$ the set of all $k$-dimensional planes $s$ in $V$ such that the restriction of $Ω$ onto $s$ is singular. For the cases when $k=2,n-2$ a simple geometric characteristic of $S^{n}_{k}(Ω)$ will be described.8pagesSymplectic Geometry53D05;14M15;51M15text