2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67362We study symplectic structures on filiform Lie algebras -- nilpotent Lie algebras of the maximal length of the descending central sequence. In the present article we classify the Lie algebras with the structure relations of the following form: $$[e_i,e_j]=(j-i)e_{i+j}+\sum_{l{=}1}c_{ij}^l e_{i+j+l}, i+j \le n.$$ In even dimensions the subspace of symplectic Lie algebras has the codimension one.26 pagesRings and AlgebrasSymplectic Geometry17B30 (Primary) 53D05 (Secondary)text