<?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>0034-7426</journal-id>
<journal-title><![CDATA[Revista Colombiana de Matemáticas]]></journal-title>
<abbrev-journal-title><![CDATA[Rev.colomb.mat.]]></abbrev-journal-title>
<issn>0034-7426</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional de Colombia y Sociedad Colombiana de Matemáticas]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-74262009000200003</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Una demostración alternativa del teorema de ultralímites]]></article-title>
<article-title xml:lang="en"><![CDATA[A proof of the ultralimits theorem]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[FORERO CUERVO]]></surname>
<given-names><![CDATA[ANDRÉS]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad de Los Andes  ]]></institution>
<addr-line><![CDATA[Bogotá ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>15</day>
<month>12</month>
<year>2009</year>
</pub-date>
<pub-date pub-type="epub">
<day>15</day>
<month>12</month>
<year>2009</year>
</pub-date>
<volume>43</volume>
<numero>2</numero>
<fpage>115</fpage>
<lpage>138</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0034-74262009000200003&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0034-74262009000200003&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0034-74262009000200003&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[En este artículo se provee una demostración alternativa del teorema de ultralímites, establecido por Kochen en 1961. Para ello se definen los modelos genéricos constantes, construidos como límites de modelos de Kripke con el mismo universo en cada nodo, con respecto a un filtro de abiertos sobre el mismo orden parcial con su topología natural.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[This paper provides an alternative proof of the Ultralimits Theorem, established by Kochen in 1961. In order to achieve this, generic constant models are defined, constructed as limits of Kripke models with the same universe on each node, with respect to a filter of open sets over the same partial order with its natural topology.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Ultrapotencias]]></kwd>
<kwd lng="es"><![CDATA[ultralímites]]></kwd>
<kwd lng="es"><![CDATA[modelos de Kripke]]></kwd>
<kwd lng="es"><![CDATA[modelos genéricos]]></kwd>
<kwd lng="es"><![CDATA[intuicionismo]]></kwd>
<kwd lng="en"><![CDATA[Ultrapowers]]></kwd>
<kwd lng="en"><![CDATA[Kripke models]]></kwd>
<kwd lng="en"><![CDATA[generic models]]></kwd>
<kwd lng="en"><![CDATA[intuitionism]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ 
<font size="2" face="verdana">

    <p>
<b>
<font size="4">
    <center>
Una demostraci&oacute;n alternativa del teorema de ultral&iacute;mites
</center>
</font>
</b>
</p>

    <p>
<b>
<font size="3">
    <center>
A proof of the ultralimits theorem
</center>
</font>
</b>
</p>

    <p>
    <center>
ANDR&Eacute;S FORERO CUERVO<sup>1</sup>
</center>
</p>

    <p>
<sup>1</sup>Universidad de Los Andes, Bogot&aacute;, Colombia. University of California, Irvine, EE.UU. Email: <a href="mailto:an-forer@uniandes.edu.co">an-forer@uniandes.edu.co</a>
    <br>
</p>

<hr size="1">

    <p>
<b>
    ]]></body>
<body><![CDATA[<center>
Resumen
</center>
</b>
</p>

    <p>
En este art&iacute;culo se provee una demostraci&oacute;n alternativa del teorema de ultral&iacute;mites, establecido por Kochen en 1961. Para ello se definen los modelos gen&eacute;ricos constantes, construidos como l&iacute;mites de modelos de Kripke con el mismo universo en cada nodo, con respecto a un filtro de abiertos sobre el mismo orden parcial con su topolog&iacute;a natural.
</p>

    <p>
<b>
Palabras clave:
</b>
Ultrapotencias,
ultral&iacute;mites,
modelos de Kripke,
modelos gen&eacute;ricos,
intuicionismo.
</p>

<hr size="1">

<i>2000 Mathematics Subject Classification: 53C21, 53C42.</i>

<hr size="1">

    <p>
<b>
    <center>
Abstract
</center>
</b>
</p>

    <p>
This paper provides an alternative proof of the Ultralimits Theorem, established by Kochen in 1961. In order to achieve this, generic constant models are defined, constructed as limits of Kripke models with the same universe on each node, with respect to a filter of open sets over the same partial order with its natural topology.
</p>

    <p>
<b>
Key words:
</b>
Ultrapowers,
Kripke models,
generic models,
intuitionism.
</p>

<hr size="1">

    <p>
Texto completo disponible en <a href="pdf/rcm/v43n2/v43n2a03.pdf">PDF</a>
</p>

<hr size="1">

    <p>
<b>
<font size="3">
Referencias
</font>
</b>
</p>


    <!-- ref --><p>
[1] J. L. Bell and A. B. Slomson, <i>Models and Ultraproducts: an Introduction</i>, North Holland Publishing Company, Amsterdam, 1969.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000022&pid=S0034-7426200900020000300001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[2] X. Caicedo, `L&oacute;gica de los haces de estructuras´, <i>Rev. Acad. Colomb. Cienc.</i> <i>19</i>,  (1995), 569-586.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000023&pid=S0034-7426200900020000300002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[3] H. D. Ebbinghaus, J. Flum, and W. Thomas, <i>Mathematical Logic</i>, Springer Verlag, New York, 1984.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000024&pid=S0034-7426200900020000300003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[4] A. Forero, Modelos gen&eacute;ricos constantes y ultrapotencias,  Tesis (Matem&aacute;tico), Universidad de Los Andes, Bogot&aacute;, 2004.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000025&pid=S0034-7426200900020000300004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[5] S. B. Kochen, `Ultraproducts in the theory of models´, <i>Ann. Math.</i> <i>74</i>, 2 (1961), 221-261.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000026&pid=S0034-7426200900020000300005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[6] S. Shelah, `Every two elementary equivalent models have isomorphic ultrapowers´, <i>Israel J. Math.</i> <i>10</i>,  (1971), 224-233.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000027&pid=S0034-7426200900020000300006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
[7] D. vanDalen, <i>Logic and Structure</i>, Springer, Berlin, 2008.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000028&pid=S0034-7426200900020000300007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><center>
<b>(Recibido en noviembre de 2008. Aceptado en octubre de 2009)</b>
</center>
<hr size="1">

    <p>
Este art&iacute;culo se puede citar en <i>LaTeX</i> utilizando la siguiente referencia bibliogr&aacute;fica de <i>BibTeX</i>:
</p>
<code><font size="2">@ARTICLE{RCMv43n2a03,    <br>
 &nbsp;&nbsp;&nbsp; AUTHOR &nbsp;= {Forero Cuervo, Andr&eacute;s},    <br>
 &nbsp;&nbsp;&nbsp; TITLE &nbsp; = {{Una demostraci&oacute;n alternativa del teorema de ultral&iacute;mites}},    ]]></body>
<body><![CDATA[<br>
 &nbsp;&nbsp;&nbsp; JOURNAL = {Revista Colombiana de Matem&aacute;ticas},    <br>
&nbsp;&nbsp;&nbsp; YEAR &nbsp;&nbsp; = {2009},    <br>
&nbsp;&nbsp;&nbsp; volume &nbsp;= {43},    <br>
&nbsp;&nbsp;&nbsp; number &nbsp;= {2},    <br>
&nbsp;&nbsp;&nbsp; pages &nbsp; = {115-138}    <br>
}</font></code>

<hr size="1">
</font>
     ]]></body><back>
<ref-list>
<ref id="B1">
<label>1</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bell]]></surname>
<given-names><![CDATA[J. L.]]></given-names>
</name>
<name>
<surname><![CDATA[Slomson]]></surname>
<given-names><![CDATA[A. B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Models and Ultraproducts: an Introduction]]></source>
<year>1969</year>
<publisher-name><![CDATA[North Holland Publishing Company]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B2">
<label>2</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Caicedo]]></surname>
<given-names><![CDATA[X.]]></given-names>
</name>
</person-group>
<article-title xml:lang="es"><![CDATA[`Lógica de los haces de estructuras´]]></article-title>
<source><![CDATA[Rev. Acad. Colomb. Cienc.]]></source>
<year>1995</year>
<volume>19</volume>
<page-range>569-586</page-range></nlm-citation>
</ref>
<ref id="B3">
<label>3</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ebbinghaus]]></surname>
<given-names><![CDATA[H. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Flum]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Thomas]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
</person-group>
<source><![CDATA[Mathematical Logic]]></source>
<year>1984</year>
<publisher-name><![CDATA[Springer Verlag]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B4">
<label>4</label><nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Forero]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Modelos genéricos constantes y ultrapotencias]]></source>
<year>2004</year>
</nlm-citation>
</ref>
<ref id="B5">
<label>5</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kochen]]></surname>
<given-names><![CDATA[S. B.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[`Ultraproducts in the theory of models´]]></article-title>
<source><![CDATA[Ann. Math.]]></source>
<year>1961</year>
<volume>74</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>221-261</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>6</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Shelah]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[`Every two elementary equivalent models have isomorphic ultrapowers´]]></article-title>
<source><![CDATA[Israel J. Math.]]></source>
<year>1971</year>
<volume>10</volume>
<page-range>224-233</page-range></nlm-citation>
</ref>
<ref id="B7">
<label>7</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[vanDalen]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<source><![CDATA[Logic and Structure]]></source>
<year>2008</year>
<publisher-name><![CDATA[Springer]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
