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Proceedings of the American Mathematical Society
Proceedings of the American Mathematical Society
ISSN 1088-6826(e) ISSN 0002-9939(p)

     

An upper bound on the dimension of the reflexivity closure

Author(s): Calin Ambrozie; Bojan Kuzma; Vladimir Müller
Journal: Proc. Amer. Math. Soc. 138 (2010), 1721-1731.
MSC (2010): Primary 47L05; Secondary 15A03
Posted: November 18, 2009
MathSciNet review: 2587457
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Abstract | References | Similar articles | Additional information

Abstract: Let $ {\mathcal V},{\mathcal W}$ be linear spaces over an algebraically closed field, and let $ \mathscr{S}$ be an $ n$-dimensional subspace of linear operators that maps $ {\mathcal V}$ into $ {\mathcal W}$. We give a sharp upper bound for the dimension of the intersection of all images of nonzero operators from $ \mathscr{S}$, namely $ \dim ( \bigcap_{A\in\mathscr{S}\setminus\{0\}}\mathrm{Im} A ) \leq \dim{\mathcal V}-n+1$. As an application, we also give a sharp upper bound for the dimension of the reflexivity closure $ \operatorname{Ref}\mathscr{S}$ of $ \mathscr{S}$, namely $ \dim ( \operatorname{Ref}\mathscr{S} ) \leq n(n+1)/2$.


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Additional Information:

Calin Ambrozie
Affiliation: Mathematical Institute of the Academy of Sciences of the Czech Republic, Zitna 25, 115 67 Prague 1, Czech Republic - and - Mathematical Institute, Bucharest, P.O. Box 1-764, RO-014700 Romania
Email: ambrozie@math.cas.cz

Bojan Kuzma
Affiliation: University of Primorska, Cankarjeva 5, SI-6000 Koper, Slovenia - and - Institute of Mathematics, Physics and Mechanics, Jadranska 19, SI-1000 Ljubljana, Slovenia
Email: bojan.kuzma@pef.upr.si

Vladimir Müller
Affiliation: Mathematical Institute of the Academy of Sciences of the Czech Republic, Zitna 25, 115 67 Prague 1, Czech Republic
Email: muller@math.cas.cz

DOI: 10.1090/S0002-9939-09-10184-3
PII: S 0002-9939(09)10184-3
Keywords: Determinantal varieties, space of linear operators, intersection of images, reflexivity defect
Received by editor(s): January 20, 2009,
Received by editor(s) in revised form: August 26, 2009
Posted: November 18, 2009
Additional Notes: The first author was supported by grants IAA 100190903 of GA AV, Cncsis 54Gr/07, Ancs CEx23-05, MEB 090905
The second author was supported by a joint Czech-Slovene grant, MEB 090905.
The third author was supported by grants No. 201/09/0473 of GA CR and IRP AV OZ 10190503
Communicated by: Nigel J. Kalton
Copyright of article: Copyright 2009, American Mathematical Society
The copyright for this article reverts to public domain after 28 years from publication.




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