JATS-0042-001
Element
*
is not allowed to be empty
JATS-0042-002
*
attribute string-join(for $a in (@*[string-length(normalize-space(.))=0] except (@close[parent::mml:mfenced]
| @open[parent::mml:mfenced] | @separators[parent::mml:mfenced])) return name($a),
', ') should not be empty.