<?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>1405-5546</journal-id>
<journal-title><![CDATA[Computación y Sistemas]]></journal-title>
<abbrev-journal-title><![CDATA[Comp. y Sist.]]></abbrev-journal-title>
<issn>1405-5546</issn>
<publisher>
<publisher-name><![CDATA[Instituto Politécnico Nacional, Centro de Investigación en Computación]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-55462021000100149</article-id>
<article-id pub-id-type="doi">10.13053/cys-25-1-3473</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Why is the Least Square Error Method Dangerous?]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Skala]]></surname>
<given-names><![CDATA[Vaclav]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Kansa]]></surname>
<given-names><![CDATA[Edward]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,University of West Bohemia Faculty of Applied Sciences ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Czech Republic</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Convergent Solutions  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>USA</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>03</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>03</month>
<year>2021</year>
</pub-date>
<volume>25</volume>
<numero>1</numero>
<fpage>149</fpage>
<lpage>151</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-55462021000100149&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-55462021000100149&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-55462021000100149&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: This contribution briefly describes some &#8221;dangerous&#8221; features of the Least Square Error (LSE) methods, which are not generally known, but often used in applications, and researchers are not aware of those. The LSE is usually used in approximations of acquired data to find &#8221;the best fit&#8221; of the data, especially in financial economics and related fields. However, the LSE method is not invariant to some standard basic operations used within a solution of a linear system of equations.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Least square error]]></kwd>
<kwd lng="en"><![CDATA[system of linear equations]]></kwd>
<kwd lng="en"><![CDATA[numerical mathematics]]></kwd>
<kwd lng="en"><![CDATA[over determined system]]></kwd>
<kwd lng="en"><![CDATA[invariant operations]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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