Document Types > Integrating the Equation Editor > Adding Equation Support to DITA Document Types > Adding Equation Support to a DITA XML Schema
Adding Equation Support to a DITA XML Schema
To support equations in a DITA XML schema, you must integrate the atieqn-d domain into your schema. The following file supports this domain:
You integrate the domain into your schema in the process defined in the XSD document-type shell: Coding requirements topic in the OASIS Darwin Information Typing Architecture (DITA) Version 1.2 standard. Follow these steps to integrate the domain into your schema:
1. Include the domain into your schema towards the top of the file, with the other domain inclusions:
<!-- ================ TOPIC DOMAINS ===================== -->
<xs:include schemaLocation="atieqnDomain.xsd"/>
2. In the MODULE INCLUDE DEFINITION section where commonElementGrp.xsd is imported, add a redefine entry integrating the domain extensions to the foreign element:
<xs:redefine schemaLocation="urn:oasis:names:tc:dita:xsd:commonElementGrp.xsd:1.3">

<xs:group name="foreign">
<xs:group ref="foreign"/>
<xs:group ref="atieqn-d-foreign"/>

<!-- ... other domain integrations ... -->
If the commonElementGrp.xsd entity is not available in the schema, find it in one of the included schemas and update it there.
3. In the INFO TYPES section, add the domain token to the domains attribute:
<xs:attributeGroup name="domains-att">
<xs:attribute name="domains" type="xs:string"
default="(topic hazard-d)
(topic hi-d)
(topic indexing-d)
(topic sw-d)
(topic pr-d)
(topic ui-d)
(topic ut-d)
(topic concept)
(topic concept glossentry)
(topic concept glossgroup)
(topic reference)
(topic task)
(topic task strictTaskbody-c)
(topic atieqn-d)
4. Add the attribute xmlns:atieqn=”http:/” to the xs:schema node in the schema.
5. The entity declaration should be added to any document and document template that uses this schema. For example,
<!DOCTYPE topic [
<!ENTITY %atieqn PUBLIC “-//Arbortext//ENTITIES Equation All//EN//XML”>