<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-04-13T02:51:36Z</responseDate><request verb="GetRecord" identifier="oai:www.recercat.cat:2117/1049" metadataPrefix="oai_dc">https://recercat.cat/oai/request</request><GetRecord><record><header><identifier>oai:recercat.cat:2117/1049</identifier><datestamp>2025-07-17T13:46:30Z</datestamp><setSpec>com_2072_1033</setSpec><setSpec>col_2072_452950</setSpec></header><metadata><oai_dc:dc xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
   <dc:title>Orbits of controllable and observable systems</dc:title>
   <dc:creator>Clotet Juan, Josep</dc:creator>
   <dc:creator>García Planas, María Isabel</dc:creator>
   <dc:contributor>Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada I</dc:contributor>
   <dc:contributor>Universitat Politècnica de Catalunya. EGSA - Equacions Diferencials, Geometria, Sistemes Dinàmics i de Control, i Aplicacions</dc:contributor>
   <dc:subject>System theory</dc:subject>
   <dc:subject>Algebras, Linear</dc:subject>
   <dc:subject>Multilinear algebra</dc:subject>
   <dc:subject>Matrices</dc:subject>
   <dc:subject>Controllability</dc:subject>
   <dc:subject>Observability</dc:subject>
   <dc:subject>Lie group action</dc:subject>
   <dc:subject>Orbits</dc:subject>
   <dc:subject>Sistemes, Teoria de</dc:subject>
   <dc:subject>Àlgebra lineal</dc:subject>
   <dc:subject>Àlgebra multilineal</dc:subject>
   <dc:subject>Matriu S, Teoria</dc:subject>
   <dc:subject>Classificació AMS::15 Linear and multilinear algebra; matrix theory</dc:subject>
   <dc:subject>Classificació AMS::93 Systems Theory; Control::93B Controllability, observability, and system structure</dc:subject>
   <dc:description>Let a time-invariant linear system $\left .\aligned \dot&#xd;
x(t)&amp;=Ax(t)+Bu(t)\\y(t)&amp;=Cx(t)\endaligned \right \}$ corresponding to a&#xd;
realization of a prescribed transfer function matrix can be represented&#xd;
by triples of matrices  $(A,B,C)$. The permitted transformations of&#xd;
basis changes in the space state on the systems can be seen in the space&#xd;
of triples of matrices as similarity equivalence. In this paper we give&#xd;
a geometric characteriaztion of controllable and observable systems as&#xd;
orbits under a Lie group action. As a corollary we obtain a lower bound&#xd;
of the distance between a controllable and observable triple and the&#xd;
nearest uncontrollable one.</dc:description>
   <dc:date>1999</dc:date>
   <dc:type>Article</dc:type>
   <dc:identifier>https://hdl.handle.net/2117/1049</dc:identifier>
   <dc:language>eng</dc:language>
   <dc:rights>http://creativecommons.org/licenses/by-nc-nd/2.5/es/</dc:rights>
   <dc:rights>Open Access</dc:rights>
   <dc:rights>Attribution-NonCommercial-NoDerivs 2.5 Spain</dc:rights>
   <dc:format>9</dc:format>
   <dc:format>application/pdf</dc:format>
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