ABSTRACT. We establish the following converse to the Eidelheit theorem: an unbounded closed and convex set of a real Hilbert space may be separated by a closed hyperplane from every other disjoint closed and convex set, if and only if it has a finite codimension and a nonempty interior with respect

inverse of a linear operator

Abstract A representation theorem for infinite-dimensional, linear control systems is proved in the context of strongly continuous semigroups in Hilbert spaces. The result allows for unbounded input and output operators and is used to derive necessary and sufficient conditions for the realizability

Abstract. We characterise imaginaries (up to interdefinability) in Hilbert spaces using a Galois theory for compact unitary groups.

Several methods for solving systems of equilibrium problems in Hilbert spaces – and for find-ing best approximations thereof – are presented and their convergence properties are established. The proposed methods include proximal-like block-iterative algorithms for general systems, as well

We consider extensions of Anosov diffeomorphisms on infranilmani-folds with Hilbert space fibers and disprove a conjecture regarding condi-tions equivalent to transitivity of such extensions. 1

ABSTRACT. Many inequalities involving real-valued convex functions can be found in the literature. Here we show how these inequalities lead to corresponding results for self-adjoint operators in Hilbert space.

the interpretation of -terms/nets as operators on the Hilbert space. 1 Presentation -Calculus is simple but not completely convincing as a real machine-language. Real machine instructions have a fixed run-time; a fi-reduction step does not. Some implementations do map fi-reductions into sequences of real

Abstract. A broken tube is a special kind of a domain in an infinite-dimensional separable Hilbert space, and it has several properties which do not occur in a finitedimensional space. 1

We prove that the operator Hilbert space OH does not embed completely isomorphically into the predual of a semi-finite von Neumann algebra. This complements Junge’s recent result that it admits such an embedding in the non semi-finite case.