2-innerproduct spaces and Gâteaux partial derivatives
A classification of projectors
A positive operator A and a closed subspace of a Hilbert space ℋ are called compatible if there exists a projector Q onto such that AQ = Q*A. Compatibility is shown to depend on the existence of certain decompositions of ℋ and the ranges of A and . It also depends on a certain angle between A() and the orthogonal of .
A generalization of parallel addition.
A Grüss type inequality for sequences of vectors in inner product spaces and applications.
A note on normability of locally convex spaces
A refinement of Hölder's inequality and applications.
A remark on the weak topology of the Hilbert space
A Remark on Two Hilbert Space Scattering Theory.
A Riccati equation arising in a boundary control problem for distributed parameters
Si prova resistenza locale della soluzione di una equazione di Riccati che si incontra in un problema di controllo ottimale. In ipotesi di regolarità per il costo si prova resistenza globale. Il problema astratto considerato è il modello di alcuni problemi di controllo ottimale governati da equazioni paraboliche con controllo sulla frontiera.
A triangle inequality for angles in a Hilbert space
An algebraic characterization of complete inner product spaces.
An identity in real inner product spaces.
An infinite-dimensional pre-Hilbert space all bounded linear operators of which are simple
An invariant subspace of the Bergman space having the codimension two property.
An isomorphic characterization of the Schmidt class
An operator on a separable Hilbert space with many hypercyclic vectors
Bessel and Grüss type inequalities in inner product modules over Banach -algebras.
Cauchy multiplication and periodic functions (mod r).
We analise periodic functions (mod r), keeping Cauchy multiplication as the basic tool, and pay particular attention to even functions (mod r) having the property f(n) = f((n,r)) for all n. We provide some new aspects into the Hilbert space structure of even functions (mod r) and make use of linera transformations to interpret the known number-theoretic formulae involving solutions of congruences.
C-Complete Systems In Normed Spaces
Central points of convex sets