<?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>S0035-001X2004000100012</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Familias de superficies nulas en el espacio-tiempo tridimensional de Minkowski y sus ecuaciones diferenciales asociadas]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Silva-Ortigoza]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Godínez]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<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>00</month>
<year>2004</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2004</year>
</pub-date>
<volume>50</volume>
<numero>1</numero>
<fpage>70</fpage>
<lpage>83</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2004000100012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2004000100012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2004000100012&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[En este trabajo describimos el procedimiento para obtener toda la familia de ecuaciones diferenciales ordinarias de tercer orden conectadas mediante una transformación de contacto tales que en su espacio de soluciones se encuentra definida una métrica conforme a la métrica tridimensional de Minkowski.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[In this work we describe the procedure to obtain all the family of third order ordinary differential equations connected by a contact transformation such that in their spaces of solutions is defined a conformal three demensional Minkowski metric.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Espacio-tiempo de Minkowski]]></kwd>
<kwd lng="es"><![CDATA[superficies nulas]]></kwd>
<kwd lng="es"><![CDATA[ecuaciones diferenciales ordinarias de tercer orden]]></kwd>
<kwd lng="en"><![CDATA[Minkowski space-time]]></kwd>
<kwd lng="en"><![CDATA[null surfaces]]></kwd>
<kwd lng="en"><![CDATA[third order ordinary differential equations]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  	    <p align="justify"><font face="verdana" size="4">Investigaci&oacute;n</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="center"><font face="verdana" size="4"><b>Familias de superficies nulas en el espacio&#45;tiempo tridimensional de Minkowski y sus ecuaciones diferenciales asociadas</b></font></p>  	    <p align="center"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="center"><font face="verdana" size="2"><b>G. Silva&#45;Ortigoza y P. Garc&iacute;a&#45;God&iacute;nez</b></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><i>Facultad de Ciencias F&iacute;sico Matem&aacute;ticas de la Universidad Aut&oacute;noma de Puebla, Apartado Postal 1152, 72001, Puebla, Pue., M&eacute;xico.</i></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2">Recibido el 20 de mayo de 2003    ]]></body>
<body><![CDATA[<br> 	Aceptado el 23 de junio de 2003</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>  	    <p align="justify"><font face="verdana" size="2">En este trabajo describimos el procedimiento para obtener toda la familia de ecuaciones diferenciales ordinarias de tercer orden conectadas mediante una transformaci&oacute;n de contacto tales que en su espacio de soluciones se encuentra definida una m&eacute;trica conforme a la m&eacute;trica tridimensional de Minkowski.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Descriptores:</b> Espacio&#45;tiempo de Minkowski; superficies nulas; ecuaciones diferenciales ordinarias de tercer orden.</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>  	    <p align="justify"><font face="verdana" size="2">In this work we describe the procedure to obtain all the family of third order ordinary differential equations connected by a contact transformation such that in their spaces of solutions is defined a conformal three demensional Minkowski metric.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Keywords:</b> Minkowski space&#45;time; null surfaces; third order ordinary differential equations.</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">PACS: 03.30.+p; 02.60.Lj</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v50n1/v50n1a12.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Agradecimientos</b></font></p>  	    <p align="justify"><font face="verdana" size="2">Los autores agradecen el apoyo econ&oacute;mico recibido de CONACyT a trav&eacute;s del proyecto 33725&#45;E. Adem&aacute;s G.S.O. agradece el apoyo econ&oacute;mico recibido del Sistema Nacional de Investigadores (M&eacute;xico). Este trabajo tambi&eacute;n fue apoyado parcialmente por la VIEP&#45;BUAP por medio del proyecto II 102I02.</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Referencias</b></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">1. S. Frittelli, C. Kozameh, and E.T. Newman, <i>J. Math. Phys.</i> <b>36</b> (1995)4975.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298731&pid=S0035-001X200400010001200001&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">2. S. Frittelli, C. Kozameh, and E.T. Newman, <i>J. Math. Phys.</i> <b>36</b> (1995) 4984.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298733&pid=S0035-001X200400010001200002&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. S. Frittelli, C. Kozameh, and E.T. Newman, <i>J. Math. Phys.</i> <b>36</b> (1995) 5005.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298735&pid=S0035-001X200400010001200003&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">4. M. Tinamoto, <i>On the Null Surface Formulation gr&#45;qc/9703003 Rev. Mex. Fis.</i> <b>50</b></font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298737&pid=S0035-001X200400010001200004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">5. D. Forni, M. Iriondo, and C. Kozameh, <i>J. Math. Phys.</i> <b>41</b> (2000) 5517.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298738&pid=S0035-001X200400010001200005&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. Frittelli, C. Kozameh, and E.T. Newman, <i>Commun. Math. Phys.</i> <b>223</b> (2001) 383.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298740&pid=S0035-001X200400010001200006&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">7. E. Cartan, <i>C. R. Acad. Sci.</i> <b>206</b> (1938) 1425.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298742&pid=S0035-001X200400010001200007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <p align="justify"><font face="verdana" size="2">8. E. Cartan, <i>Rev. Mat. Hispano&#45;Amer.</i> <b>4</b> (1941) 1.</font></p>  	    <p align="justify"><font face="verdana" size="2">9. E. Cartan, <i>Ann. Sc. Ec. Norm. Sup.</i> 3e serie <b>60</b> (1943) 1.</font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">10. S.S. Chern, <i>Selected Papers</i> (Springer&#45;Verlag 1978, original 1940).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298746&pid=S0035-001X200400010001200008&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">11. S. Frittelli, N. Kamran, and E.T. Newman, <i>J. Geom.Phys.</i> <b>43</b> (2002) 133.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298748&pid=S0035-001X200400010001200009&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">12. P.J.O. Olver, <i>Equivalence, Invariants and Symmetry</i> (Cambridge University Press, 1995).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8298750&pid=S0035-001X200400010001200010&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <p align="justify"><font face="verdana" size="2">13. Ver la secci&oacute;n sobre la teor&iacute;a de Hamilton&#45;Jacobi, en L.D. Landau and E.M. Lifshitz, <i>Classical Mechanics</i> (Pergamon, Headington Hill Hall, &Oacute;xford, 1960).</font></p>  	    ]]></body>
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