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Semivariation in L p -spaces

Brian Jefferies, Susumu Okada (2005)

Commentationes Mathematicae Universitatis Carolinae

Suppose that X and Y are Banach spaces and that the Banach space X ^ τ Y is their complete tensor product with respect to some tensor product topology τ . A uniformly bounded X -valued function need not be integrable in X ^ τ Y with respect to a Y -valued measure, unless, say, X and Y are Hilbert spaces and τ is the Hilbert space tensor product topology, in which case Grothendieck’s theorem may be applied. In this paper, we take an index 1 p < and suppose that X and Y are L p -spaces with τ p the associated L p -tensor product...

Semivariations of an additive function on a Boolean ring

Zbigniew Lipecki (2009)

Colloquium Mathematicae

With an additive function φ from a Boolean ring A into a normed space two positive functions on A, called semivariations of φ, are associated. We characterize those functions as submeasures with some additional properties in the general case as well as in the cases where φ is bounded or exhaustive.

Sequential closures of σ -subalgebras for a vector measure

Werner J. Ricker (1996)

Commentationes Mathematicae Universitatis Carolinae

Let X be a locally convex space, m : Σ X be a vector measure defined on a σ -algebra Σ , and L 1 ( m ) be the associated (locally convex) space of m -integrable functions. Let Σ ( m ) denote { χ E ; E Σ } , equipped with the relative topology from L 1 ( m ) . For a subalgebra 𝒜 Σ , let 𝒜 σ denote the generated σ -algebra and 𝒜 ¯ s denote the sequential closure of χ ( 𝒜 ) = { χ E ; E 𝒜 } in L 1 ( m ) . Sets of the form 𝒜 ¯ s arise in criteria determining separability of L 1 ( m ) ; see [6]. We consider some natural questions concerning 𝒜 ¯ s and, in particular, its relation to χ ( 𝒜 σ ) . It is shown that...

Set valued measures and integral representation

Xiao Ping Xue, Cheng Lixin, Goucheng Li, Xiao Bo Yao (1996)

Commentationes Mathematicae Universitatis Carolinae

The extension theorem of bounded, weakly compact, convex set valued and weakly countably additive measures is established through a discussion of convexity, compactness and existence of selection of the set valued measures; meanwhile, a characterization is obtained for continuous, weakly compact and convex set valued measures which can be represented by Pettis-Aumann-type integral.

Sobre les variacions de valoracions vectorials.

María Congost Iglesias (1981)

Stochastica

In this note we define three variations for a vector valued function defined on an inf-semilattice, all of them generalizations of those considered for vector valued set-functions. We are interested in additive and finiteness properties of such variations.

Some fixed point theorems and existence of weak solutions of Volterra integral equation under Henstock-Kurzweil-Pettis integrability

Afif Ben Amar (2011)

Commentationes Mathematicae Universitatis Carolinae

In this paper we examine the set of weakly continuous solutions for a Volterra integral equation in Henstock-Kurzweil-Pettis integrability settings. Our result extends those obtained in several kinds of integrability settings. Besides, we prove some new fixed point theorems for function spaces relative to the weak topology which are basic in our considerations and comprise the theory of differential and integral equations in Banach spaces.

Some remarks on descriptive characterizations of the strong McShane integral

Sokol Bush Kaliaj (2019)

Mathematica Bohemica

We present the full descriptive characterizations of the strong McShane integral (or the variational McShane integral) of a Banach space valued function f : W X defined on a non-degenerate closed subinterval W of m in terms of strong absolute continuity or, equivalently, in terms of McShane variational measure V F generated by the primitive F : W X of f , where W is the family of all closed non-degenerate subintervals of W .

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