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Double sequence spaces over n -normed spaces

Kuldip Raj, Sunil K. Sharma (2014)

Archivum Mathematicum

In this paper, we define some classes of double sequences over n -normed spaces by means of an Orlicz function. We study some relevant algebraic and topological properties. Further some inclusion relations among the classes are also examined.

Doubly commuting submodules of the Hardy module over polydiscs

Jaydeb Sarkar, Amol Sasane, Brett D. Wick (2013)

Studia Mathematica

In this note we establish a vector-valued version of Beurling’s theorem (the Lax-Halmos theorem) for the polydisc. As an application of the main result, we provide necessary and sufficient conditions for the “weak” completion problem in H ( ) .

Drop property on locally convex spaces

Ignacio Monterde, Vicente Montesinos (2008)

Studia Mathematica

A single technique provides short proofs of some results about drop properties on locally convex spaces. It is shown that the quasi drop property is equivalent to a drop property for countably closed sets. As a byproduct, we prove that the drop and quasi drop properties are separably determined.

Dual Banach algebras: representations and injectivity

Matthew Daws (2007)

Studia Mathematica

We study representations of Banach algebras on reflexive Banach spaces. Algebras which admit such representations which are bounded below seem to be a good generalisation of Arens regular Banach algebras; this class includes dual Banach algebras as defined by Runde, but also all group algebras, and all discrete (weakly cancellative) semigroup algebras. Such algebras also behave in a similar way to C*- and W*-algebras; we show that interpolation space techniques can be used in place of GNS type arguments....

Dual complementors in topological algebras

Marina Haralampidou (2005)

Banach Center Publications

We deal with dual complementors on complemented topological (non-normed) algebras and give some characterizations of a dual pair of complementors for some classes of complemented topological algebras. The study of dual complementors shows their deep connection with dual algebras. In particular, we refer to Hausdorff annihilator locally C*-algebras and to proper Hausdorff orthocomplemented locally convex H*-algebras. These algebras admit, by their nature, the same type of dual pair of complementors....

Dual renormings of Banach spaces

Petr Hájek (1996)

Commentationes Mathematicae Universitatis Carolinae

We prove that a Banach space admitting an equivalent WUR norm is an Asplund space. Some related dual renormings are also presented.

Dual Spaces and Hahn-Banach Theorem

Keiko Narita, Noboru Endou, Yasunari Shidama (2014)

Formalized Mathematics

In this article, we deal with dual spaces and the Hahn-Banach Theorem. At the first, we defined dual spaces of real linear spaces and proved related basic properties. Next, we defined dual spaces of real normed spaces. We formed the definitions based on dual spaces of real linear spaces. In addition, we proved properties of the norm about elements of dual spaces. For the proof we referred to descriptions in the article [21]. Finally, applying theorems of the second section, we proved the Hahn-Banach...

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