"some" and "every" are not opposites

      <xsl:stylesheet
                  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                  version="2.0">
            <xsl:output  method="xml"
                        indent="yes"
                        omit-xml-declaration="yes"/>

            <xsl:template  match="/aaa">
                  <xxx>
                        <xsl:value-of  select="if (some $a in (1 to 20) satisfies $a>0) then 1 else 0"/>
                  </xxx>
                  <yyy>
                        <xsl:value-of  select="if (every $a in (1 to 20) satisfies $a>0) then 1 else 0"/>
                  </yyy>
            </xsl:template>

      </xsl:stylesheet>

      <aaa/>

      <xxx>1</xxx>
      <yyy>1</yyy>