<?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>S0034-74262013000200003</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Descripción de la clase de Nikolski\u\i-Besov disminuyendo su parámetro de suavidad, mediante derivadas fraccionarias débiles]]></article-title>
<article-title xml:lang="en"><![CDATA[Description of the Nikolski\u\i-Besov Class Decreasing its Smoothness Parameter using Weak Fractional Derivatives]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[ENRÍQUEZ]]></surname>
<given-names><![CDATA[FRANCISCO]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[PÉREZ]]></surname>
<given-names><![CDATA[JHON]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad del Cauca  ]]></institution>
<addr-line><![CDATA[Popayán ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad del Cauca  ]]></institution>
<addr-line><![CDATA[Popayán ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>15</day>
<month>12</month>
<year>2013</year>
</pub-date>
<pub-date pub-type="epub">
<day>15</day>
<month>12</month>
<year>2013</year>
</pub-date>
<volume>47</volume>
<numero>2</numero>
<fpage>149</fpage>
<lpage>165</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0034-74262013000200003&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0034-74262013000200003&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0034-74262013000200003&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Los espacios de Nikolskii-Besov Bpq&alpha;\big(Rn\big)&equiv; Bpq&alpha;, 1&le; p,\,q&le;&infin;, &alpha;>0, se han descrito recientemente con ayuda de las derivadas fraccionarias de Caputo. Usando el concepto de derivada fraccionaria débil, en el presente trabajo se reduce la caracterización de Bpq&alpha; al caso Bpq&gamma;, donde &gamma; es cualquier número positivo estrictamente menor que &alpha;.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[The Nikolski\u\i-Besov spaces Bpq&alpha;\big(Rn\big)&equiv; Bpq&alpha;, 1&le; p,\,q&le;&infin;, &alpha;>0, recently were described using the Caputo's fractional derivative. Using the concept of weak fractional derivative, in this paper we reduces the characterization of Bpq&alpha; to the case Bpq&gamma;, where &gamma; is any positive number strictly less than &alpha;.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Espacios de Nikolski\u\i-Besov]]></kwd>
<kwd lng="es"><![CDATA[derivada fraccionaria]]></kwd>
<kwd lng="es"><![CDATA[núcleo de Poisson]]></kwd>
<kwd lng="es"><![CDATA[integral de Poisson]]></kwd>
<kwd lng="en"><![CDATA[Nikolski\u\i-Besov spaces]]></kwd>
<kwd lng="en"><![CDATA[Fractional derivative]]></kwd>
<kwd lng="en"><![CDATA[Poisson kernel]]></kwd>
<kwd lng="en"><![CDATA[Poisson integral]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  <font size="2" face="verdana">     <p> <b> <font size="4">       <center>     Descripci&oacute;n de la clase de Nikolskii-Besov disminuyendo su par&aacute;metro de suavidad, mediante derivadas fraccionarias d&eacute;biles   </center>   </font> </b> </p>     <p> <b> <font size="3">       <center>     Description of the  Nikolskii-Besov Class Decreasing its Smoothness Parameter using Weak Fractional Derivatives   </center>   </font> </b> </p>     <p>       <center>     FRANCISCO ENR&Iacute;QUEZ<sup>1</sup>,     JHON P&Eacute;REZ<sup>2</sup>   </center> </p>     <p> <sup>1</sup>Universidad del Cauca, Popay&aacute;n, Colombia. Email: <a href="mailto:enriquezfran@unicauca.edu.co">enriquezfran@unicauca.edu.co</a>     <br>   <sup>2</sup>Universidad del Cauca, Popay&aacute;n, Colombia. Email: <a href="mailto:jjperez@unicauca.edu.co">jjperez@unicauca.edu.co</a>     <br> </p> <hr size="1">     ]]></body>
<body><![CDATA[<p> <b>       <center>     Resumen   </center>   </b> </p>     <p> Los espacios de Nikolskii-Besov <i>B<sub>pq</sub><sup>&alpha;</sup>(<b>R</b><sup>n</sup>)&equiv; B<sub>pq</sub><sup>&alpha;</sup></i>, <i>1&le; p, q&le;&infin;</i>, <i>&alpha;&gt;0</i>, se han descrito recientemente con ayuda de las derivadas fraccionarias de Caputo. Usando el concepto de derivada fraccionaria d&eacute;bil, en el presente trabajo se reduce la caracterizaci&oacute;n de <i>B<sub>pq</sub><sup>&alpha;</sup></i> al caso <i>B<sub>pq</sub><sup>&gamma;</sup></i>, donde <i>&gamma;</i> es cualquier n&uacute;mero positivo estrictamente menor que <i>&alpha;</i>. </p>     <p> <b> Palabras clave: </b> Espacios de  Nikolskii-Besov,   derivada fraccionaria,   n&uacute;cleo de Poisson,   integral de Poisson. </p> <hr size="1"> <i>2000 Mathematics Subject Classification: 26A33, 26A16..</i> <hr size="1">     <p> <b>       <center>     Abstract   </center>   </b> </p>     <p> The Nikolskii-Besov spaces <i>B<sub>pq</sub><sup>&alpha;</sup>(<b>R</b><sup>n</sup>)&equiv; B<sub>pq</sub><sup>&alpha;</sup></i>, <i>1&le; p, q&le;&infin;</i>, <i>&alpha;&gt;0</i>, recently were described using the Caputo's fractional derivative. Using the concept of weak fractional derivative, in this paper we reduces the characterization of <i>B<sub>pq</sub><sup>&alpha;</sup></i> to the case <i>B<sub>pq</sub><sup>&gamma;</sup></i>, where <i>&gamma;</i> is any positive number strictly less than <i>&alpha;</i>. </p>     <p> <b> Key words: </b> Nikolskii-Besov spaces,   Fractional derivative,   Poisson kernel,   Poisson integral. </p> <hr size="1">     <p> Texto completo disponible en <a href="pdf/rcm/v47n2/v47n2a03.pdf">PDF</a> </p> <hr size="1">     <p> <b> <font size="3"> Referencias </font> </b> </p>     ]]></body>
<body><![CDATA[<!-- ref --><p> [1] O. V. Besov and V. P. I. y. S. M. Nikolsky, <i>Integral Representations of Functions and Imbedding Theorems</i>, V. H. Winston, 1979.    &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=S0034-7426201300020000300001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>     <!-- ref --><p> [2] F. Enriquez, M. A., and P. J., `Caracterizaci&oacute;n de los espacios de lipschitz a trav&eacute;s de las derivadas fraccionarias seg&uacute;n liouville´, <i>Matematicas: Ense&ntilde;anza Universitaria</i> <i>XVII</i>, 2 (2009), 57-72.    &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=S0034-7426201300020000300002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>     <!-- ref --><p> [3] F. Enr&iacute;quez, M. A., and P. J., `A Characterization of Structural Nikolskii-Besov Spaces using Fractional Derivatives´, <i>Bolet&iacute;n de Matem&aacute;ticas</i> <i>17</i>, 1 (2010), 77-98.    &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=S0034-7426201300020000300003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>     <!-- ref --><p> [4] E. M. Stein, <i>Singular Integrals and Differentiability Properties of Functions</i>, Princenton University Press, New Jersey, USA, 1970.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000029&pid=S0034-7426201300020000300004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p> <hr size="1">     <center>   <b>(Recibido en diciembre de 2012. Aceptado en septiembre de 2013)</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" face="verdana"> @ARTICLE{RCMv47n2a03,    ]]></body>
<body><![CDATA[<br> &nbsp;&nbsp;&nbsp; AUTHOR &nbsp;= {Enr&iacute;quez, Francisco and P&eacute;rez, Jhon},    <br> &nbsp;&nbsp;&nbsp; TITLE &nbsp; = {{Descripci&oacute;n de la clase de Nikolskii-Besov disminuyendo su par&aacute;metro de suavidad, mediante derivadas fraccionarias d&eacute;biles}},    <br> &nbsp;&nbsp;&nbsp; JOURNAL = {Revista Colombiana de Matem&aacute;ticas},    <br> &nbsp;&nbsp;&nbsp; YEAR &nbsp;&nbsp; = {2013},    <br> &nbsp;&nbsp;&nbsp; volume &nbsp;= {47},    <br> &nbsp;&nbsp;&nbsp; number &nbsp;= {2},    <br> &nbsp;&nbsp;&nbsp; pages &nbsp; = {149--165}    <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[Besov]]></surname>
<given-names><![CDATA[O. V.]]></given-names>
</name>
<name>
<surname><![CDATA[Nikolsky]]></surname>
<given-names><![CDATA[V. P. I. y. S. M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Integral Representations of Functions and Imbedding Theorems]]></source>
<year>1979</year>
<publisher-name><![CDATA[V. H. Winston]]></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[Enriquez]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[A.]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[J.]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
</person-group>
<article-title xml:lang="es"><![CDATA[`Caracterización de los espacios de lipschitz a través de las derivadas fraccionarias según liouville´]]></article-title>
<source><![CDATA[Matematicas: Enseñanza Universitaria]]></source>
<year>2009</year>
<volume>XVII</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>57-72</page-range></nlm-citation>
</ref>
<ref id="B3">
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<person-group person-group-type="author">
<name>
<surname><![CDATA[Enríquez]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[A.]]></surname>
<given-names><![CDATA[M.]]></given-names>
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<name>
<surname><![CDATA[J.]]></surname>
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<article-title xml:lang="en"><![CDATA[`A Characterization of Structural Nikolskii-Besov Spaces using Fractional Derivatives´]]></article-title>
<source><![CDATA[Boletín de Matemáticas]]></source>
<year>2010</year>
<volume>17</volume>
<numero>1</numero>
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<name>
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<given-names><![CDATA[E. M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Singular Integrals and Differentiability Properties of Functions]]></source>
<year>1970</year>
<publisher-loc><![CDATA[New Jersey ]]></publisher-loc>
<publisher-name><![CDATA[Princenton University Press]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
