Used to mark text that should appear lower than the baseline and slightly smaller; inferior or subscript text.
<!ELEMENT sub (#PCDATA %emphasized-text;)* >
(#PCDATA | email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | alternatives | inline-graphic | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup | x | break)*
Any combination of:
<abbrev>, <abbrev-journal-title>, <addr-line>, <aff>, <alt-title>, <anonymous>, <article-title>, <attrib>, <award-id>, <bold>, <chapter-title>, <chem-struct>, <collab>, <comment>, <compound-kwd-part>, <compound-subject-part>, <conf-acronym>, <conf-loc>, <conf-name>, <conf-num>, <conf-sponsor>, <conf-theme>, <copyright-holder>, <copyright-statement>, <corresp>, <def-head>, <degrees>, <disp-formula>, <edition>, <element-citation>, <email>, <etal>, <ext-link>, <fax>, <funding-source>, <funding-statement>, <given-names>, <gov>, <history>, <inline-formula>, <inline-supplementary-material>, <institution>, <issue>, <issue-part>, <issue-sponsor>, <issue-title>, <italic>, <journal-subtitle>, <journal-title>, <kwd>, <label>, <license-p>, <meta-name>, <meta-value>, <mixed-citation>, <monospace>, <named-content>, <on-behalf-of>, <overline>, <p>, <part-title>, <patent>, <phone>, <prefix>, <preformat>, <product>, <publisher-loc>, <publisher-name>, <related-article>, <related-object>, <role>, <roman>, <sans-serif>, <sc>, <self-uri>, <series>, <series-text>, <series-title>, <sig>, <sig-block>, <source>, <speaker>, <std>, <std-organization>, <strike>, <string-conf>, <string-date>, <string-name>, <styled-content>, <sub>, <subject>, <subtitle>, <suffix>, <sup>, <supplement>, <surname>, <target>, <td>, <term>, <term-head>, <textual-form>, <th>, <title>, <trans-source>, <trans-subtitle>, <trans-title>, <underline>, <unstructured-kwd-group>, <uri>, <verse-line>, <volume>, <volume-id>, <volume-series>, <x>, <xref>
An ordinary subscript:
... <p>This article by Peter Wilmshurst (10 October 1998, pp 996-9) used the incorrect abbreviation for inspired partial pressure of oxygen. The abbreviation should have been Pi<sc>o</sc><sub>2</sub> not Fi<sc>o</sc><sub>2</sub>.</p> ...
As shown formatted above, a subscript and superscript in a “stacked” arrangement:
...
<body>
<p>The <italic>Escherichia coli argU</italic> gene encodes a minor arginine
tRNA, tRNA<sup arrange="stack">Arg</sup><sub arrange="stack">UCU</sub>,
which corresponds to the rare codon AGA and possibly AGG ....</p>
...
</body>
...
JATS-format1.ent