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L. A. Nazarova

Publications and source records attributed to L. A. Nazarova.

6 recordsLinked to original sources

Orthoscalar representations of quivers on the category of Hilberts spaces. II

As it is known, finitely presented quivers correspond to Dynkin graphs (Gabriel, 1972) and tame quivers -- to extended Dynkin graphs (Donovan and Freislich, Nazarova, 1973). In the article "Locally scalar reresentations of graphs in the category of Hilbers spaces" (Func. Anal. and Appl., 2005) authors showed the way to tranfer these results to Hilbert spaces, constructed Coxeter functors and proved an analogue of Gabriel theorem fol locally scalar (orthoscalar in the sequel) representations (up to the unitary equivalence). The category of orthoscalar representations of a quiver can be considered as a subcategory in the category of all representations (over a field $\mathbb C$). In the present paper we study the connection between indecomposable orthoscalar representations in the subcategory and in the category of all representations. For the quivers, corresponded to extended Dynkin graphs, orthoscalar representations which cannot be obtained from the simplest by Coxeter functors (regular representations) are classified.

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Matrix Problems in Hilbert Spaces

We consider matrix problems in Hilbert spaces (orthoscalar representations of quivers and posets). A criterion of tameness of the problem of classification of indecomposable orthoscalar representations of a quiver is given.

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Antimonotonous quadratic forms and partially ordered sets

Antimonotonous quadratic forms generalizing P-faithful posets defined by authors earlier are introduced. The criterion of antimonotonousness is given for posets with positive semidefinite quadratic forms. As consequence the new proofs of the criterions of finite representativity and tameness of posets are given.

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