<returnvalue>Top.Child1</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <function>subpath</function> ( <type>ltree</type>, <parameter>offset</parameter> <type>integer</type> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns subpath of <type>ltree</type> starting at
        position <parameter>offset</parameter>, extending to end of path.
        If <parameter>offset</parameter> is negative, subpath starts that far
        from the end of the path.
       </para>
       <para>
        <literal>subpath('Top.Child1.Child2', 1)</literal>
        <returnvalue>Child1.Child2</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>nlevel</primary></indexterm>
        <function>nlevel</function> ( <type>ltree</type> )
        <returnvalue>integer</returnvalue>
       </para>
       <para>
        Returns number of labels in path.
       </para>
       <para>
        <literal>nlevel('Top.Child1.Child2')</literal>
        <returnvalue>3</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>index</primary></indexterm>
        <function>index</function> ( <parameter>a</parameter> <type>ltree</type>, <parameter>b</parameter> <type>ltree</type> )
        <returnvalue>integer</returnvalue>
       </para>
       <para>
        Returns position of first occurrence of <parameter>b</parameter> in
        <parameter>a</parameter>, or -1 if not found.
       </para>
       <para>
        <literal>index('0.1.2.3.5.4.5.6.8.5.6.8', '5.6')</literal>
        <returnvalue>6</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <function>index</function> ( <parameter>a</parameter> <type>ltree</type>,  <parameter>b</parameter> <type>ltree</type>, <parameter>offset</parameter> <type>integer</type> )
        <returnvalue>integer</returnvalue>
       </para>
       <para>
        Returns position of first occurrence of <parameter>b</parameter>
        in <parameter>a</parameter>, or -1 if not found.  The search starts at
        position <parameter>offset</parameter>;
        negative <parameter>offset</parameter> means
        start <parameter>-offset</parameter> labels from the end of the path.
       </para>
       <para>
        <literal>index('0.1.2.3.5.4.5.6.8.5.6.8', '5.6', -4)</literal>
        <returnvalue>9</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>text2ltree</primary></indexterm>
        <function>text2ltree</function> ( <type>text</type> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Casts <type>text</type> to <type>ltree</type>.
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>ltree2text</primary></indexterm>
        <function>ltree2text</function> ( <type>ltree</type> )
        <returnvalue>text</returnvalue>
       </para>
       <para>
        Casts <type>ltree</type> to <type>text</type>.
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>lca</primary></indexterm>
        <function>lca</function> ( <type>ltree</type> <optional>, <type>ltree</type> <optional>, ... </optional></optional> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Computes longest common ancestor of paths
        (up to 8 arguments are supported).
       </para>
       <para>
        <literal>lca('1.2.3', '1.2.3.4.5.6')</literal>
        <returnvalue>1.2</returnvalue>
       </para></entry>
      </row>