On the Kreĭn-Langer integral representation of generalized Nevanlinna functions.
On the Lebesgue decomposition of Gleason measures
On the ordered sets in -dimensional real inner product spaces.
On the products of quantum logics
On the radius of a set in a Hilbert space
On the semi-inner product in locally convex spaces.
On the Stability of the Functional Quadratic on A-orthogonal Vectors
On the volume method in the study of Auerbach bases of finite-dimensional normed spaces
In this note we show that if the ratio of the minimal volume V of n-dimensional parallelepipeds containing the unit ball of an n-dimensional real normed space X to the maximal volume v of n-dimensional crosspolytopes inscribed in this ball is equal to n!, then the relation of orthogonality in X is symmetric. Hence we deduce the following properties: (i) if V/v=n! and if n>2, then X is an inner product space; (ii) in every finite-dimensional normed space there exist at least two different Auerbach...
On three problems from the Scottish Book connected with orthogonal systems
On Typical Compact Convex Sets in Hilbert Spaces
Let E be an infinite dimensional separable space and for e ∈ E and X a nonempty compact convex subset of E, let qX(e) be the metric antiprojection of e on X. Let n ≥ 2 be an arbitrary integer. It is shown that for a typical (in the sence of the Baire category) compact convex set X ⊂ E the metric antiprojection qX(e) has cardinality at least n for every e in a dense subset of E.
On vectorial inner product spaces
Let be a real linear space. A vectorial inner product is a mapping from into a real ordered vector space with the properties of a usual inner product. Here we consider to be a -regular Yosida space, that is a Dedekind complete Yosida space such that , where is the set of all hypermaximal bands in . In Theorem 2.1.1 we assert that any -regular Yosida space is Riesz isomorphic to the space of all bounded real-valued mappings on a certain set . Next we prove Bessel Inequality and Parseval...
On Wigner's theorem: Remarks, complements, comments, and corollaries.
Order properties of splitting subspaces in an inner product space
Original title unknown
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Orthogonal constant mappings in isosceles orthogonal spaces
Orthogonality in normed linear spaces: a classification of the different concepts and some open problems.
Orthogonality in inner products is a binary relation that can be expressed in many ways without explicit mention to the inner product of the space. Great part of such definitions have also sense in normed linear spaces. This simple observation is at the base of many concepts of orthogonality in these more general structures. Various authors introduced such concepts over the last fifty years, although the origins of some of the most interesting results that can be obtained for these generalized concepts...
Ortogonalidad en espacios normados generalizados.
Some generalized notions of James' orthogonality and orthogonality in the Pythagorean sense are defined and studied in the case of generalized normed spaces derived from generalized inner products.
Ortogonalita na množinách