|<xsl:variable name="v:title-groups"
   |              as="element()+">
   |   <xsl:sequence select="$v:user-title-groups"/>
   |   <title xpath="self::db:section|self::db:sect1                 |self::db:sect2|self::db:sect3|self::db:sect4|self::db:sect5                 |self::db:refsection|self::db:refsect1|self::db:refsect2|self::db:refsect3"
   |          group="{if (f:is-true($section-numbers))                  then 'title-numbered'                  else 'title-unnumbered'}"/>
   |   <title xpath="self::db:article|self::db:preface|self::db:chapter|self::db:appendix"
   |          group="{if (f:is-true($component-numbers))                  then 'title-numbered'                  else 'title-unnumbered'}"/>
   |   <title xpath="self::db:set" group="title-unnumbered"/>
   |   <title xpath="self::db:book|self::db:part|self::db:reference"
   |          group="{if (f:is-true($division-numbers))                  then 'title-numbered'                  else 'title-unnumbered'}"/>
   |   <title xpath="self::db:figure[parent::db:formalgroup]                 |self::db:table[parent::db:formalgroup]                 |self::db:equation[parent::db:formalgroup]                 |self::db:example[parent::db:formalgroup]"
   |          group="subfigure-title"/>
   |   <title xpath="self::db:figure|self::db:table|self::db:equation|self::db:example|self::db:procedure"
   |          group="title-numbered"/>
   |   <title xpath="self::db:formalgroup" group="title-numbered"/>
   |   <title xpath="self::db:step|self::db:listitem[parent::db:orderedlist]"
   |          group="title-unnumbered"/>
   |   <title xpath="self::db:glosssee|self::db:glossseealso"
   |          group="title-unnumbered"/>
   |   <title xpath="self::db:see|self::db:seealso" group="title-unnumbered"/>
   |   <title xpath="self::db:question|self::db:answer" group="title-numbered"/>
   |   <title xpath="self::*" group="title-unnumbered"/>
   |</xsl:variable>