<bicond>

<bicond> (雙條件功能結構限制) 定義一個雙條件功能結構限制；結果和前提被指明為功能結構或功能結構群組；若兩者皆包含一個已知功能結構、或兩者皆不包含，則結果符合需求。 [18.11 Feature System Declaration]
組件 iso-fs — Feature Structures
屬性 att.global (@xml:id, @n, @xml:lang, @xml:base, @xml:space) (att.global.rendition (@rend, @style, @rendition)) (att.global.linking (@corresp, @synch, @sameAs, @copyOf, @next, @prev, @exclude, @select)) (att.global.analytic (@ana)) (att.global.facs (@facs)) (att.global.change (@change)) (att.global.responsibility (@cert, @resp)) (att.global.source (@source))
可包含在於
iso-fs: fsConstraints
可包含
iso-fs: f fs iff
例子
<bicond>
 <fs>
  <f name="FOO">
   <symbol value="42"/>
  </f>
 </fs>
 <iff/>
 <fs>
  <f name="BAR">
   <binary value="true"/>
  </f>
 </fs>
</bicond>
Content model 
<content>
 <sequence>
  <alternate>
   <elementRef key="fs"/>
   <elementRef key="f"/>
  </alternate>
  <elementRef key="iff"/>
  <alternate>
   <elementRef key="fs"/>
   <elementRef key="f"/>
  </alternate>
 </sequence>
</content>
宣告 
<rng:element name="bicond">
 <rng:ref name="att.global.attributes"/>
 <rng:ref name="att.global.rendition.attributes"/>
 <rng:ref name="att.global.linking.attributes"/>
 <rng:ref name="att.global.analytic.attributes"/>
 <rng:ref name="att.global.facs.attributes"/>
 <rng:ref name="att.global.change.attributes"/>
 <rng:ref name="att.global.responsibility.attributes"/>
 <rng:ref name="att.global.source.attributes"/>
 <rng:group>
  <rng:choice>
   <rng:ref name="fs"/>
   <rng:ref name="f"/>
  </rng:choice>
  <rng:ref name="iff"/>
  <rng:choice>
   <rng:ref name="fs"/>
   <rng:ref name="f"/>
  </rng:choice>
 </rng:group>
</rng:element>
element bicond
{
   att.global.attributes,
   att.global.rendition.attributes,
   att.global.linking.attributes,
   att.global.analytic.attributes,
   att.global.facs.attributes,
   att.global.change.attributes,
   att.global.responsibility.attributes,
   att.global.source.attributes,
   ( ( fs | f ), iff, ( fs | f ) )
}