On semi-inner product spaces, I
On semi-inner product spaces, II
On Solèr's characterization of Hilbert spaces.
On solvability of fourth order operator-diferential equations of elliptic type on weight spaces.
On some global and local geometric properties of Calderón-Lozanovskiĭ spaces
Criteria for full k-rotundity (k ∈ ℕ, k ≥ 2) and uniform rotundity in every direction of Calderón-Lozanovskiĭ spaces are formulated. A characterization of -points in these spaces is also given.
On some properties of Banach operators.
On some properties of Banach operators. II.
On spectral distributions of definitizable operators in Krein space
On strictly convex and strictly 2-convex 2-normed spaces. II.
On the angles between certain arithmetically defined subspaces of
If and are two families of unitary bases for , and is a fixed number, let and be subspaces of spanned by vectors in and respectively. We study the angle between and as goes to infinity. We show that when and arise in certain arithmetically defined families, the angles between and may either tend to or be bounded away from zero, depending on the behavior of an associated eigenvalue problem.
On the approximation of continuosly diffentialble functions in Hilbert spaces
On the -angle and -angle in normed spaces.
On the characterization of weak closure in Hilbert space
On the closure of the sum of closed subspaces.
On the Definition of a Quadratic Form
On the definition of fuzzy Hilbert spaces and its application.
On the Definition of Hilbert Space.
On the dependence of the orthogonal projector on deformations of the scalar product
We consider scalar products on a given Hilbert space parametrized by bounded positive and invertible operators defined on this space, and orthogonal projectors onto a fixed closed subspace of the initial Hilbert space corresponding to these scalar products. We show that the projector is an analytic function of the scalar product, we give the explicit formula for its Taylor expansion, and we prove some algebraic formulas for projectors.
On the existence of configurations of subspaces in a Hilbert space with fixed angles.
On the homotopical classification of DJ-mappings of infnitely dimensional spheres