<?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>S0034-74262015000100004</article-id>
<article-id pub-id-type="doi">10.15446/recolma.v49n1.54165</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Grüss Type Inequalities for Complex Functions Defined on Unit Circle with Applications for Unitary Operators in Hilbert Spaces]]></article-title>
<article-title xml:lang="es"><![CDATA[Desigualdades de tipo Grüss para funciones complejas definidas sobre el círculo unitario con aplicaciones para operadores en espacios Hilbert]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[DRAGOMIR]]></surname>
<given-names><![CDATA[SILVESTRU SEVER]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Victoria University  ]]></institution>
<addr-line><![CDATA[Melbourne ]]></addr-line>
<country>Australia</country>
</aff>
<pub-date pub-type="pub">
<day>15</day>
<month>06</month>
<year>2015</year>
</pub-date>
<pub-date pub-type="epub">
<day>15</day>
<month>06</month>
<year>2015</year>
</pub-date>
<volume>49</volume>
<numero>1</numero>
<fpage>77</fpage>
<lpage>94</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0034-74262015000100004&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0034-74262015000100004&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0034-74262015000100004&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Some Grüss type inequalities for the Riemann-Stieltjes integral of continuous complex valued integrands defined on the complex unit circle C( 0,1) and various subclasses of integrators are given. Natural applications for functions of unitary operators in Hilbert spaces are provided.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Se proporcionan algunas desigualdades tipo Grüss para la integral de Riemann-Stieltjes de integrandos de valores continuos complejos definidos sobre el circulo unitario complejo C(0,1) y varias subclases de integradores son dados. Aplicaciones naturales para funciones de operadores unitarios en espacios de Hilbert son proporcionadas.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Grüss type inequalities]]></kwd>
<kwd lng="en"><![CDATA[Riemann-Stieltjes integral inequalities]]></kwd>
<kwd lng="en"><![CDATA[Unitary operators in Hilbert spaces]]></kwd>
<kwd lng="en"><![CDATA[Spectral theory]]></kwd>
<kwd lng="en"><![CDATA[Quadrature rules]]></kwd>
<kwd lng="es"><![CDATA[Desigualdades de tipo Grüss]]></kwd>
<kwd lng="es"><![CDATA[desigualdades integrales de Riemann-Stieltjes]]></kwd>
<kwd lng="es"><![CDATA[Operadores unitarios en espacios de Hilbert]]></kwd>
<kwd lng="es"><![CDATA[teoria espectral]]></kwd>
<kwd lng="es"><![CDATA[reglas de cuadratura]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  <font size="2" face="verdana">    <P>Doi: <a href="http://dx.doi.org/10.15446/recolma.v49n1.54165" target="_blank">http://dx.doi.org/10.15446/recolma.v49n1.54165</a></P>      <p> <b> <font size="4">     <center> Gr&uuml;ss Type Inequalities for Complex Functions Defined on Unit Circle with Applications for Unitary Operators in Hilbert Spaces </center> </font> </b> </p>      <p> <b> <font size="3">     <center> Desigualdades de tipo Gr&uuml;ss para funciones complejas definidas sobre el c&iacute;rculo unitario con aplicaciones para operadores en espacios Hilbert </center> </font> </b> </p>      <p>     <center> SILVESTRU SEVER DRAGOMIR<sup>1</sup> </center> </p>      <p> <sup>1</sup>Victoria University, Melbourne, Australia. Email: <a href="mailto:sever.dragomir@vu.edu.au">sever.dragomir@vu.edu.au</a>     <br> </p>  <hr size="1">      ]]></body>
<body><![CDATA[<p> <b>     <center> Abstract </center> </b> </p>      <p> Some Gr&uuml;ss type inequalities for the Riemann-Stieltjes integral of continuous complex valued integrands defined on the complex unit circle <i>C( 0,1) </i> and various subclasses of integrators are given. Natural applications for functions of unitary operators in Hilbert spaces are provided. </p>      <p> <b> Key words: </b> Gr&uuml;ss type inequalities, Riemann-Stieltjes integral inequalities, Unitary operators in Hilbert spaces, Spectral theory, Quadrature rules. </p>  <hr size="1">  <i>2000 Mathematics Subject Classification: 26D15, 41A51, 47A63.</i>  <hr size="1">      <p> <b>     <center> Resumen </center> </b> </p>      <p> Se proporcionan algunas desigualdades tipo Gr&uuml;ss para la integral de Riemann-Stieltjes de integrandos de valores continuos complejos definidos sobre el circulo unitario complejo <i>C(0,1)</i> y varias subclases de integradores son dados. Aplicaciones naturales para funciones de operadores unitarios en espacios de Hilbert son proporcionadas. </p>      <p> <b> Palabras clave: </b> Desigualdades de tipo Gr&uuml;ss, desigualdades integrales de Riemann-Stieltjes, Operadores unitarios en espacios de Hilbert, teoria espectral, reglas de cuadratura. </p>  <hr size="1">      <p> Texto completo disponible en <a href="pdf/rcm/v49n1/v49n1a04.pdf">PDF</a> </p>  <hr size="1">      <p> <b> <font size="3"> References </font> </b> </p>       ]]></body>
<body><![CDATA[<!-- ref --><p> [1] M. W. Alomari, `A Companion of Ostrowski's Inequality for the Riemann-Stieltjes Integral <i>\int<sub>a</sub><sup>b</sup>f(t)\,du(t)</i>, where <i>f</i> is of Bounded Variation and <i>u</i> is of <i>r-H</i>-H&ouml;lder Type and Applications´, <i>Appl. Math. Comput.</i> <i>219</i>, 9 (2013), 4792-4799.    &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=S0034-7426201500010000400001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> [2] G. A. Anastassiou, `A New Expansion Formula´, <i>Cubo Mat. Educ.</i> <i>5</i>, 1 (2003), 25-31.    &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=S0034-7426201500010000400002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> [3] S. S. Dragomir, `On the Ostrowski's Inequality for Riemann-Stieltjes Integral and Applications´, <i>Korean J. Comput. & Appl. Math</i> <i>7</i>, 3 (2000), 611-627.    &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=S0034-7426201500010000400003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> [4] S. S. Dragomir, `Sharp Bounds of \vCeby\vsev Functional for Stieltjes Integrals and Applications´, <i>Bull. Austral. Math. Soc.</i> <i>67</i>, 2 (2003), 257-266.    &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=S0034-7426201500010000400004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> [5] S. S. Dragomir, `Approximating the Riemann-Stieltjes Integral by a Trapezoidal Quadrature Rule With Applications´, <i>Mathematical and Computer Modelling</i> <i>54</i>,  (2011), 243-260.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000031&pid=S0034-7426201500010000400005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      ]]></body>
<body><![CDATA[<!-- ref --><p> [6] S. S. Dragomir, `Inequalities of Lipschitz Type for Power Series in Banach Algebras´, <i>RGMIA Research Report Collection</i> <i>15</i>, 77 (2012), 17 pp.. Preprint, Online http://rgmia.org/v15.php &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000033&pid=S0034-7426201500010000400006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p> [7] G. Helmberg, <i>Introduction to Spectral Theory in Hilbert Space</i>, John Wiley, New York, USA, 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=000034&pid=S0034-7426201500010000400007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> [8] Z. Liu, `Refinement of an Inequality of Gr&uuml;ss Type for Riemann-Stieltjes Integral´, <i>Soochow J. Math.</i> <i>30</i>, 4 (2004), 483-489.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000036&pid=S0034-7426201500010000400008&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>  <hr size="1">      <center> <b>(Recibido en febrero de 2014. Aceptado en diciembre de 2014)</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">    <P>Doi: http://dx.doi.org/ @ARTICLE{RCMv49n1a04,    <br>  &nbsp;&nbsp;&nbsp; AUTHOR &nbsp;= {Dragomir, Silvestru Sever},    <br>  &nbsp;&nbsp;&nbsp; TITLE &nbsp; = {{Gr&uuml;ss Type Inequalities for Complex Functions Defined on Unit Circle with Applications for Unitary Operators in Hilbert Spaces}},    ]]></body>
<body><![CDATA[<br>  &nbsp;&nbsp;&nbsp; JOURNAL = {Revista Colombiana de Matem&aacute;ticas},    <br> &nbsp;&nbsp;&nbsp; YEAR &nbsp;&nbsp; = {2015},    <br> &nbsp;&nbsp;&nbsp; volume &nbsp;= {49},    <br> &nbsp;&nbsp;&nbsp; number &nbsp;= {1},    <br> &nbsp;&nbsp;&nbsp; pages &nbsp; = {77--94}    <br> } </font></code>  <hr size="1"> </font>      ]]></body><back>
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