Storozh, O. G. Problem on density of some manifolds in Hilbert space. (English) Zbl 1094.46503 Mat. Stud. 24, No. 1, 111-112 (2005). Summary: One problem on density of some linear manifolds in Hilbert space is formulated. MSC: 46C20 Spaces with indefinite inner product (Kreĭn spaces, Pontryagin spaces, etc.) 47A55 Perturbation theory of linear operators Keywords:Hilbert space; density; manifold PDFBibTeX XMLCite \textit{O. G. Storozh}, Mat. Stud. 24, No. 1, 111--112 (2005; Zbl 1094.46503)