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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Change of the congruence canonical form of 2-by-2 and 3-by-3 matrices under perturbations and bundles of matrices under congruence

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Author(s):
Dmytryshyn, Andrii [1, 2] ; Futorny, Vyacheslav [3] ; Kagstrom, Bo [1, 2] ; Klimenko, Lena [4] ; Sergeichuk, Vladimir V. [5]
Total Authors: 5
Affiliation:
[1] Umea Univ, Dept Comp Sci, S-90187 Umea - Sweden
[2] Umea Univ, HPC2N, S-90187 Umea - Sweden
[3] Univ Sao Paulo, Dept Math, BR-05508 Sao Paulo - Brazil
[4] Natl Tech Univ Ukraine, Kyiv Polytech Inst, Kiev - Ukraine
[5] Ukrainian Acad Sci, Inst Math, Kiev - Ukraine
Total Affiliations: 5
Document type: Journal article
Source: Linear Algebra and its Applications; v. 469, p. 305-334, MAR 15 2015.
Web of Science Citations: 5
Abstract

We construct the Hasse diagrams G(2) and G(3) for the closure ordering on the sets of congruence classes of 2 x 2 and 3 x 3 complex matrices. In other words, we construct two directed graphs whose vertices are 2 x 2 or, respectively, 3 x 3 canonical matrices under congruence, and there is a directed path from A to B if and only if A can be transformed by an arbitrarily small perturbation to a matrix that is congruent to B. A bundle of matrices under congruence is defined as a set of square matrices A for which the pencils A)AT belong to the same bundle under strict equivalence. In support of this definition, we show that all matrices in a congruence bundle of 2 x 2 or 3 x 3 matrices have the same properties with respect to perturbations. We construct the Hasse diagrams G(2)(B) and G(3)(B) for the closure ordering on the sets of congruence bundles of 2 x 2 and, respectively, 3 x 3 matrices. We find the isometry groups of 2 x 2 and 3 x 3 congruence canonical matrices. (C) 2014 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 10/50347-9 - Algebras, representations e applications
Grantee:Ivan Chestakov
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 12/18139-2 - Methods of representation theory in linear algebra
Grantee:Vyacheslav Futorny
Support Opportunities: Research Grants - Visiting Researcher Grant - International