<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2003000500010</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Symplectic structures and Hamiltonians of a mechanical system]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Torres del Castillo]]></surname>
<given-names><![CDATA[G.F.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mendoza Torres]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Benemérita Universidad Autónoma de Puebla Instituto de Ciencias Departamento de Física Matemática]]></institution>
<addr-line><![CDATA[Puebla ]]></addr-line>
<country>México</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Benemérita Universidad Autónoma de Puebla Facultad de Ciencias Físico Matemáticas ]]></institution>
<addr-line><![CDATA[Puebla ]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>10</month>
<year>2003</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>10</month>
<year>2003</year>
</pub-date>
<volume>49</volume>
<numero>5</numero>
<fpage>445</fpage>
<lpage>449</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2003000500010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2003000500010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2003000500010&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[It is shown that in the case of a mechanical system with a finite number of degrees of freedom in classical mechanics, any constant of motion can be used as Hamiltonian by defining appropriately the symplectic structure of the phase space (or, equivalently, the Poisson bracket) and that for a given constant of motion, there are infinitely many symplectic structures that reproduce the equations of motion of the system.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Se muestra que en el caso de un sistema mecánico con un número finito de grados de libertad en la mecánica clásica, cualquier constante de movimiento puede usarse como hamiltoniana definiendo apropiadamente la estructura simpléctica del espacio fase (o, equivalentemente, el paréntesis de Poisson) y que para una constante de movimiento dada, existe una infinidad de estructuras simplécticas que reproducen las ecuaciones de movimiento del sistema.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Symplectic structure]]></kwd>
<kwd lng="en"><![CDATA[Hamilton equations]]></kwd>
<kwd lng="es"><![CDATA[Estructura simpléctica]]></kwd>
<kwd lng="es"><![CDATA[ecuaciones de Hamilton]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="justify"><font face="verdana" size="4">Investigaci&oacute;n</font></p>     <p align="justify">&nbsp;</p>      <p align="center"><font face="verdana" size="4"><b>Symplectic structures and Hamiltonians of a mechanical system</b></font></p>     <p align="center">&nbsp;</p>     <p align="center"><font face="verdana" size="2"><b>G.F. Torres del Castillo<sup>1</sup>, G. Mendoza Torres<sup>2</sup></b></font></p>      <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><i><sup>1</sup> Departamento de F&iacute;sica Matem&aacute;tica, Instituto de Ciencias, Universidad Aut&oacute;noma de Puebla,</i> <i>72570 Puebla, Pue., M&eacute;xico</i></font></p>      <p align="justify"><font face="verdana" size="2"><i><sup>2</sup> Facultad de Ciencias F&iacute;sico Matem&aacute;ticas, Universidad Aut&oacute;noma de Puebla, Apartado Postal 1152, 72001 Puebla, Pue., M&eacute;xico</i></font></p>      <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2">Recibido el 6 de mayo de 2003.     ]]></body>
<body><![CDATA[<br>   Aceptado el 12 de junio de 2003.</font></p>      <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>      <p align="justify"><font face="verdana" size="2">It is shown that in the case of a mechanical system with a finite number of degrees of freedom in classical mechanics, any constant of motion can be used as Hamiltonian by defining appropriately the symplectic structure of the phase space (or, equivalently, the Poisson bracket) and that for a given constant of motion, there are infinitely many symplectic structures that reproduce the equations of motion of the system.</font></p>      <p align="justify"><font face="verdana" size="2"><b>Keywords:</b> Symplectic structure; Hamilton equations.</font></p>      <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>      <p align="justify"><font face="verdana" size="2">Se muestra que en el caso de un sistema mec&aacute;nico con un n&uacute;mero finito de grados de libertad en la mec&aacute;nica cl&aacute;sica, cualquier constante de movimiento puede usarse como hamiltoniana definiendo apropiadamente la estructura simpl&eacute;ctica del espacio fase (o, equivalentemente, el par&eacute;ntesis de Poisson) y que para una constante de movimiento dada, existe una infinidad de estructuras simpl&eacute;cticas que reproducen las ecuaciones de movimiento del sistema.</font></p>      <p align="justify"><font face="verdana" size="2"><b>Palabras clave:</b> Estructura simpl&eacute;ctica; ecuaciones de Hamilton.</font></p>      <p align="justify"><font face="verdana" size="2">PACS: 45.05.+x; 45.20.&#45;d</font></p>     ]]></body>
<body><![CDATA[<p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v49n5/v49n5a10.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>     <p align="justify">&nbsp;</p>      <p align="justify"><font face="verdana" size="2"><b>References</b></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">1. D. ter Haar, <i>Elements</i> <i>of</i> <i>Hamiltonian</i> <i>Mechanics,</i> 2nd ed. (Pergamon, Oxford, 1971).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296492&pid=S0035-001X200300050001000001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">2. C. Lanczos, <i>The</i> <i>Variational</i> <i>Principles</i> <i>of</i> <i>Mechanics,</i> 4th ed. (Dover, New York, 1986).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296494&pid=S0035-001X200300050001000002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">3. G.F. Torres del Castillo and D. Acosta Avalos, <i>Rev.</i> <i>Mex.</i> <i>F&iacute;s.</i> 40 (1994) 405.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296496&pid=S0035-001X200300050001000003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      ]]></body>
<body><![CDATA[<!-- ref --><p align="justify"><font face="verdana" size="2">4. M. Montesinos, <i>Phys.</i> <i>Rev.</i> <i>A</i> 68 (2003) 014101.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296498&pid=S0035-001X200300050001000004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">5. G.F. Torres del Castillo and E. Galindo Linares, <i>Rev.</i> <i>Mex.</i> <i>F&iacute;s.</i> 49 (2003) 344.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296500&pid=S0035-001X200300050001000005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">6. S. Sternberg, <i>Lectures</i> <i>on</i> <i>Differential</i> <i>Geometry,</i> 2nd ed. (Chelsea, New York, 1983).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8296502&pid=S0035-001X200300050001000006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>     ]]></body><back>
<ref-list>
<ref id="B1">
<label>1</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[ter Haar]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<source><![CDATA[Elements of Hamiltonian Mechanics]]></source>
<year>1971</year>
<edition>2</edition>
<publisher-loc><![CDATA[Oxford ]]></publisher-loc>
<publisher-name><![CDATA[Pergamon]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B2">
<label>2</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lanczos]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[The Variational Principles of Mechanics]]></source>
<year>1986</year>
<edition>4</edition>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Dover]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B3">
<label>3</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Torres del Castillo]]></surname>
<given-names><![CDATA[G.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Acosta Avalos]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<source><![CDATA[Rev. Mex. Fís.]]></source>
<year>1994</year>
<volume>40</volume>
<page-range>405</page-range></nlm-citation>
</ref>
<ref id="B4">
<label>4</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Montesinos]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Phys. Rev. A]]></source>
<year>2003</year>
<volume>68</volume>
<page-range>014101</page-range></nlm-citation>
</ref>
<ref id="B5">
<label>5</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Torres del Castillo]]></surname>
<given-names><![CDATA[G.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Galindo Linares]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Rev. Mex. Fís.]]></source>
<year>2003</year>
<volume>49</volume>
<page-range>344</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>6</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sternberg]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Lectures on Differential Geometry]]></source>
<year>1983</year>
<edition>2</edition>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Chelsea]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
