<xsd:schema 
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   xmlns:xlink="http://www.w3.org/1999/xlink"
>
   <xsd:simpleType name="restrictedBoolean">
      <xsd:annotation>
      <xsd:documentation xml:lang="en">
      MathML only permits true and false in boolean values; whereas the XML
      Schema boolean datatype allows 0 and 1 as well.
      </xsd:documentation>
      </xsd:annotation>
      <xsd:restriction base="xsd:boolean">
         <xsd:pattern value="true|false"/>
      </xsd:restriction>
   </xsd:simpleType>

   <!-- Attributes shared by all elements  .......................... -->

   <xsd:attributeGroup name="MATHML.Common.attrib">
      <!--     <xsd:attribute ref='xlink:href' use='optional'/> -->
      <xsd:attribute name="class" type="xsd:string" use="optional"/>
      <xsd:attribute name="style" type="xsd:string" use="optional"/>
      <xsd:attribute name="id" type="xsd:ID" use="optional"/>
      <xsd:attribute name="xref" type="xsd:IDREF" use="optional"/>
      <xsd:attribute name="other" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <!-- Presentation element set  ................................... -->

   <!-- Attribute definitions -->

   <xsd:simpleType name="fontfamily-type">
      <xsd:restriction base="xsd:string"/>
   </xsd:simpleType>

   <!-- MathML2 typographically-distinguished symbol attributes -->

   <xsd:simpleType name="mathvariant-type">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="normal"/>
         <xsd:enumeration value="bold"/>
         <xsd:enumeration value="italic"/>
         <xsd:enumeration value="bold-italic"/>
         <xsd:enumeration value="double-struck"/>
         <xsd:enumeration value="bold-fraktur"/>
         <xsd:enumeration value="script"/>
         <xsd:enumeration value="bold-script"/>
         <xsd:enumeration value="fraktur"/>
         <xsd:enumeration value="sans-serif"/>
         <xsd:enumeration value="bold-sans-serif"/>
         <xsd:enumeration value="sans-serif-italic"/>
         <xsd:enumeration value="sans-serif-bold-italic"/>
       <xsd:enumeration value="monospace"/>
     </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="size-enumeration">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="small"/>
         <xsd:enumeration value="normal"/>
         <xsd:enumeration value="big"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="v-unit">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="em"/>
         <xsd:enumeration value="ex"/>
         <xsd:enumeration value="px"/>
         <xsd:enumeration value="in"/>
         <xsd:enumeration value="cm"/>
         <xsd:enumeration value="mm"/>
         <xsd:enumeration value="pt"/>
         <xsd:enumeration value="pc"/>
         <xsd:enumeration value="%"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="number-and-v-unit-intermediate">
      <xsd:list>
         <xsd:simpleType>
             <xsd:union memberTypes="xsd:decimal v-unit"/>
          </xsd:simpleType>
      </xsd:list>
   </xsd:simpleType>

   <xsd:simpleType name="number-and-v-unit">
      <xsd:restriction base="number-and-v-unit-intermediate">
         <xsd:length value="2"/>
      </xsd:restriction>
   </xsd:simpleType>

   <!-- xsd:string because spec allows 12pt  -->
   <xsd:simpleType name="vsize-type">
      <xsd:union memberTypes="number-and-v-unit xsd:string"/>
   </xsd:simpleType>

   <xsd:simpleType name="mathsize-type">
      <xsd:union memberTypes="size-enumeration vsize-type"/>
   </xsd:simpleType>

   <xsd:simpleType name="html-color-name">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="aqua"/>
         <xsd:enumeration value="black"/>
         <xsd:enumeration value="blue"/>
         <xsd:enumeration value="fushcia"/>
         <xsd:enumeration value="gray"/>
         <xsd:enumeration value="green"/>
         <xsd:enumeration value="lime"/>
         <xsd:enumeration value="maroon"/>
         <xsd:enumeration value="navy"/>
         <xsd:enumeration value="olive"/>
         <xsd:enumeration value="purple"/>
         <xsd:enumeration value="red"/>
         <xsd:enumeration value="silver"/>
         <xsd:enumeration value="teal"/>
         <xsd:enumeration value="white"/>
         <xsd:enumeration value="yellow"/>
         <xsd:enumeration value="AQUA"/>
         <xsd:enumeration value="BLACK"/>
         <xsd:enumeration value="BLUE"/>
         <xsd:enumeration value="FUSHCIA"/>
         <xsd:enumeration value="GRAY"/>
         <xsd:enumeration value="GREEN"/>
         <xsd:enumeration value="LIME"/>
         <xsd:enumeration value="MAROON"/>
         <xsd:enumeration value="NAVY"/>
         <xsd:enumeration value="OLIVE"/>
         <xsd:enumeration value="PURPLE"/>
         <xsd:enumeration value="RED"/>
         <xsd:enumeration value="SILVER"/>
         <xsd:enumeration value="TEAL"/>
         <xsd:enumeration value="WHITE"/>
         <xsd:enumeration value="YELLOW"/>
         <xsd:enumeration value="Aqua"/>
         <xsd:enumeration value="Black"/>
         <xsd:enumeration value="Blue"/>
         <xsd:enumeration value="Fushcia"/>
         <xsd:enumeration value="Gray"/>
         <xsd:enumeration value="Green"/>
         <xsd:enumeration value="Lime"/>
         <xsd:enumeration value="Maroon"/>
         <xsd:enumeration value="Navy"/>
         <xsd:enumeration value="Olive"/>
         <xsd:enumeration value="Purple"/>
         <xsd:enumeration value="Red"/>
         <xsd:enumeration value="Silver"/>
         <xsd:enumeration value="Teal"/>
         <xsd:enumeration value="White"/>
         <xsd:enumeration value="Yellow"/>
       <!-- This is incomplete. Since these are not case-sensitive, we really 
       have to put in all possible combinations of uPpeR and lOwer case. 
       That seems like overkill, in practice.-->
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="rgb-color">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="#[0-9A-Fa-f]{2}[0-9A-Fa-f]{2}([0-9A-Fa-f]{2})?"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="color-type">
      <xsd:union memberTypes="html-color-name rgb-color"/>
   </xsd:simpleType>

   <xsd:attributeGroup name="att-fontinfo">
      <xsd:attribute name="fontsize" type="xsd:string" use="optional"/>
      <xsd:attribute name="fontweight" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="normal"/>
               <xsd:enumeration value="bold"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="fontstyle" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="normal"/>
               <xsd:enumeration value="italic"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="fontfamily" type="fontfamily-type" use="optional"/>
      <xsd:attribute name="color" type="color-type" use="optional"/>
      <xsd:attribute name="mathvariant" type="mathvariant-type" use="optional"/>
      <xsd:attribute name="mathsize" type="mathsize-type" use="optional"/>
      <xsd:attribute name="mathcolor" type="color-type" use="optional"/>
      <xsd:attribute name="mathbackground" type="color-type" use="optional"/>
   </xsd:attributeGroup>

   <xsd:simpleType name="h-unit">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="em"/>
         <xsd:enumeration value="ex"/>
         <xsd:enumeration value="px"/>
         <xsd:enumeration value="in"/>
         <xsd:enumeration value="cm"/>
         <xsd:enumeration value="mm"/>
         <xsd:enumeration value="pt"/>
         <xsd:enumeration value="pc"/>
         <xsd:enumeration value="%"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="number-and-h-unit-intermediate">
      <xsd:list>
         <xsd:simpleType>
            <xsd:union memberTypes="xsd:decimal h-unit"/>
         </xsd:simpleType>
      </xsd:list>
   </xsd:simpleType>

   <xsd:simpleType name="number-and-h-unit">
      <xsd:restriction base="number-and-h-unit-intermediate">
         <xsd:length value="2"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="namedspace">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="veryverythinmathspace"/>
         <xsd:enumeration value="verythinmathspace"/>
         <xsd:enumeration value="thinmathspace"/>
         <xsd:enumeration value="mediummathspace"/>
         <xsd:enumeration value="thickmathspace"/>
         <xsd:enumeration value="verythickmathspace"/>
         <xsd:enumeration value="veryverythickmathspace"/>
      </xsd:restriction>
   </xsd:simpleType>

   <!-- xsd:string because spec allows 12pt  -->
   <xsd:simpleType name="hsize-type">
      <xsd:union memberTypes="number-and-h-unit xsd:string"/>
   </xsd:simpleType>

   <xsd:simpleType name="space-type">
      <xsd:union memberTypes="namedspace hsize-type"/>
   </xsd:simpleType>

   <!-- xsd:string because spec allows 12pt  -->
   <xsd:simpleType name="size-type">
      <xsd:union memberTypes="namedspace number-and-h-unit number-and-v-unit xsd:decimal xsd:string"/>
   </xsd:simpleType>

   <xsd:simpleType name="infinity">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="infinity"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="accent-type">
      <xsd:restriction base="restrictedBoolean"/>
   </xsd:simpleType>

   <xsd:attributeGroup name="att-opinfo">
      <xsd:attribute name="form" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="prefix"/>
               <xsd:enumeration value="infix"/>
               <xsd:enumeration value="postfix"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="fence" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="separator" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="lspace" type="space-type" use="optional"/>
      <xsd:attribute name="rspace" type="space-type" use="optional"/>
      <xsd:attribute name="stretchy" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="symmetric" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="maxsize" use="optional">
         <xsd:simpleType>
            <xsd:union memberTypes="infinity size-type"/>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="minsize" type="size-type" use="optional"/>
      <xsd:attribute name="largeop" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="movablelimits" type="restrictedBoolean" use="optional"/>
      <xsd:attribute name="accent" type="accent-type" use="optional"/>
   </xsd:attributeGroup>

   <xsd:simpleType name="linebreak-type">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="auto"/>
         <xsd:enumeration value="newline"/>
         <xsd:enumeration value="indentingnewline"/>
         <xsd:enumeration value="nobreak"/>
         <xsd:enumeration value="goodbreak"/>
         <xsd:enumeration value="badbreak"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:attributeGroup name="att-sizeinfo">
      <xsd:attribute name="width" type="space-type" use="optional"/>
      <xsd:attribute name="height" type="vsize-type" use="optional"/>
      <xsd:attribute name="depth" type="vsize-type" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-quotes">
      <xsd:attribute name="lquote" type="xsd:string" use="optional"/>
      <xsd:attribute name="rquote" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <xsd:simpleType name="linethickness-enumeration">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="thin"/>
         <xsd:enumeration value="medium"/>
         <xsd:enumeration value="thick"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="linethickness-type">
      <xsd:union memberTypes="linethickness-enumeration xsd:decimal vsize-type"/>
   </xsd:simpleType>

   <xsd:attributeGroup name="att-openclose">
      <xsd:attribute name="open" type="xsd:string" use="optional"/>
      <xsd:attribute name="close" type="xsd:string" use="optional"/>
      <xsd:attribute name="separators" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-subscriptshift">
      <xsd:attribute name="subscriptshift" type="vsize-type" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-superscriptshift">
      <xsd:attribute name="superscriptshift" type="vsize-type" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-accentunder">
      <xsd:attribute name="accentunder" type="restrictedBoolean" use="optional"/>
   </xsd:attributeGroup>

   <xsd:simpleType name="align-enumeration">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="top"/>
         <xsd:enumeration value="bottom"/>
         <xsd:enumeration value="center"/>
         <xsd:enumeration value="baseline"/>
         <xsd:enumeration value="axis"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="rownumber">
      <xsd:restriction base="xsd:integer">
         <xsd:minInclusive value="1"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="align-list">
      <xsd:list itemType="align-enumeration"/>
   </xsd:simpleType>

   <xsd:attributeGroup name="att-align">
      <xsd:attribute name="rowalign" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="align-list">
               <xsd:minLength value="1"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="columnalign" type="xsd:string" use="optional"/>
      <xsd:attribute name="groupalign" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-tableinfo">
      <xsd:attribute name="align" use="optional">
         <xsd:simpleType>
            <xsd:union memberTypes="align-enumeration rownumber"/>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attributeGroup ref="att-align"/>
      <xsd:attribute name="columnwidth" type="xsd:string" use="optional"/>
      <xsd:attribute name="alignmentscope" type="xsd:string" use="optional"/>
      <xsd:attribute name="rowspacing" type="xsd:string" use="optional"/>
      <xsd:attribute name="columnspacing" type="xsd:string" use="optional"/>
      <xsd:attribute name="rowlines" type="xsd:string" use="optional"/>
      <xsd:attribute name="columnlines" type="xsd:string" use="optional"/>
      <xsd:attribute name="frame" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="none"/>
               <xsd:enumeration value="solid"/>
               <xsd:enumeration value="dashed"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="framespacing" type="xsd:string" use="optional"/>
      <xsd:attribute name="equalrows" type="xsd:string" use="optional"/>
      <xsd:attribute name="equalcolumns" type="xsd:string" use="optional"/>
      <xsd:attribute name="displaystyle" type="restrictedBoolean" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-spans">
      <xsd:attribute name="rowspan" type="xsd:string" use="optional"/>
      <xsd:attribute name="columnspan" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-edge">
      <xsd:attribute name="edge" use="optional">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="left"/>
               <xsd:enumeration value="right"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-actiontypeselection">
      <xsd:attribute name="actiontype" type="xsd:string" use="optional"/>
      <xsd:attribute name="selection" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <xsd:simpleType name="alignment-type">
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="left"/>
         <xsd:enumeration value="center"/>
         <xsd:enumeration value="right"/>
      </xsd:restriction>
   </xsd:simpleType>

   <!-- Presentation schemata with content -->

   <xsd:element name="Presentation" abstract="true">
      <xsd:annotation>
      <xsd:documentation xml:lang="en">
      All presentation constructs.
      </xsd:documentation>
      </xsd:annotation>
   </xsd:element>

   <xsd:element name="PresInCont" abstract="true" substitutionGroup="Presentation">
      <xsd:annotation>
      <xsd:documentation xml:lang="en">
       This element for substitution into content constructs excludes elements
       that are not valid as expressions.
      </xsd:documentation>
      </xsd:annotation>
   </xsd:element>

   <xsd:element name="ptoken-elt" abstract="true" substitutionGroup="PresInCont"/>

   <xsd:complexType name="ptoken" mixed="true">
      <xsd:choice minOccurs="0" maxOccurs="unbounded">
         <xsd:element ref="mglyph"/>
         <xsd:element ref="malignmark"/>
      </xsd:choice>
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      <xsd:attributeGroup ref="att-fontinfo"/>
   </xsd:complexType>

   <xsd:element name="mi" type="ptoken" substitutionGroup="ptoken-elt"/>

   <xsd:element name="mn" type="ptoken" substitutionGroup="ptoken-elt"/>

   <xsd:element name="mo" substitutionGroup="ptoken-elt">
      <xsd:complexType mixed="true">
         <xsd:complexContent mixed="true">
            <xsd:extension base="ptoken">
               <xsd:attributeGroup ref="att-opinfo"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mtext" type="ptoken" substitutionGroup="ptoken-elt"/>

   <xsd:element name="ms" substitutionGroup="ptoken-elt">
      <xsd:complexType mixed="true">
         <xsd:complexContent mixed="true">
            <xsd:extension base="ptoken">
               <xsd:attributeGroup ref="att-quotes"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Empty presentation schemata -->

   <xsd:element name="petoken-elt" abstract="true" substitutionGroup="PresInCont"/>

   <xsd:element name="mspace" substitutionGroup="petoken-elt">
      <xsd:complexType>
         <xsd:attributeGroup ref="att-sizeinfo"/>
         <xsd:attribute name="linebreak" type="linebreak-type" use="optional"/>
         <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      </xsd:complexType>
   </xsd:element>

   <!-- Presentation layout schemata  -->

   <xsd:element name="plschema-elt" abstract="true" substitutionGroup="PresInCont"/>

   <!-- Presentation: general layout schemata -->

   <xsd:element name="pgenschema-elt" abstract="true" substitutionGroup="plschema-elt"/>

   <xsd:element name="mrow" type="PresExpression" substitutionGroup="pgenschema-elt"/>

   <xsd:element name="mfrac" substitutionGroup="pgenschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attribute name="bevelled" type="xsd:string" use="optional"/>
               <xsd:attribute name="linethickness" type="linethickness-type" use="optional"/>
               <!-- The spec references these two, but the DTD does not -->
               <xsd:attribute name="numalign" type="alignment-type" use="optional"/>
               <xsd:attribute name="denoalign" type="alignment-type" use="optional"/>
            </xsd:extension>
        </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="msqrt" type="PresExpression" substitutionGroup="pgenschema-elt"/>

   <xsd:element name="mroot" type="PresExpression" substitutionGroup="pgenschema-elt"/>

   <xsd:element name="menclose" substitutionGroup="pgenschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
              <xsd:attribute name="notation" default="longdiv">
                 <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                       <xsd:enumeration value="longdiv"/>
                       <xsd:enumeration value="actuarial"/>
                       <xsd:enumeration value="radical"/>
                     </xsd:restriction>
                   </xsd:simpleType>
               </xsd:attribute>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mstyle" substitutionGroup="pgenschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-fontinfo"/>
               <xsd:attributeGroup ref="att-opinfo"/>
               <xsd:attributeGroup ref="att-quotes"/>
               <xsd:attribute name="linethickness" type="linethickness-type" use="optional"/>
               <xsd:attribute name="scriptlevel" type="xsd:integer" use="optional"/>
               <xsd:attribute name="scriptsizemultiplier" type="xsd:decimal" use="optional"/>
               <xsd:attribute name="scriptminsize" type="vsize-type" use="optional"/>
               <xsd:attribute name="background" use="optional">
                  <xsd:simpleType>
                     <xsd:union memberTypes="color-type">
                        <xsd:simpleType>
                           <xsd:restriction base="xsd:string">
                              <xsd:enumeration value="transparent"/>
                           </xsd:restriction>
                        </xsd:simpleType>
                     </xsd:union>
                  </xsd:simpleType>
               </xsd:attribute>
               <xsd:attribute name="veryverythinmathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="verythinmathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="thinmathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="mediummathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="thickmathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="verythickmathspace" type="hsize-type" use="optional"/>
               <xsd:attribute name="veryverythickmathspace" type="hsize-type" use="optional"/>
               <xsd:attributeGroup ref="att-openclose"/>
               <xsd:attributeGroup ref="att-subscriptshift"/>
               <xsd:attributeGroup ref="att-superscriptshift"/>
               <xsd:attributeGroup ref="att-accentunder"/>
               <xsd:attributeGroup ref="att-tableinfo"/>
               <xsd:attributeGroup ref="att-spans"/>
               <xsd:attributeGroup ref="att-edge"/>
               <xsd:attributeGroup ref="att-actiontypeselection"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="merror" type="PresExpression" substitutionGroup="pgenschema-elt"/>

   <!-- XYZZY: mpadded height, width, lspace, depth attributes take a different type  -->
   <xsd:element name="mpadded" substitutionGroup="pgenschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-sizeinfo"/>
               <xsd:attribute name="lspace" type="space-type" use="optional"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mphantom" type="PresExpression" substitutionGroup="pgenschema-elt"/>

   <xsd:element name="mfenced" substitutionGroup="pgenschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-openclose"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Presentation layout schemata: scripts and limits -->

   <xsd:element name="pscrschema-elt" abstract="true" substitutionGroup="plschema-elt"/>

   <xsd:element name="msub" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-subscriptshift"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="msup" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-superscriptshift"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="msubsup" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-subscriptshift"/>
               <xsd:attributeGroup ref="att-superscriptshift"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="munder" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-accentunder"/> <!-- XYZZY: not use=optional?-->
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mover" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attribute name="accent" type="accent-type"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="munderover" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attribute name="accent" type="accent-type"/>
               <xsd:attributeGroup ref="att-accentunder"/> <!-- XYZZY: not use=optional? -->
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mmultiscripts" substitutionGroup="pscrschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-subscriptshift"/>
               <xsd:attributeGroup ref="att-superscriptshift"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Presentation layout schemata: empty elements for scripts -->

   <xsd:element name="pscreschema-elt" abstract="true" substitutionGroup="Presentation"/>

   <xsd:element name="mprescripts" substitutionGroup="pscreschema-elt">
      <xsd:complexType/>
   </xsd:element>

   <xsd:element name="none" substitutionGroup="pscreschema-elt">
      <xsd:complexType/>
   </xsd:element>

   <!-- Presentation layout schemata: tables -->

   <xsd:element name="ptabschema-elt" abstract="true" substitutionGroup="plschema-elt"/>

   <xsd:element name="mtable" substitutionGroup="ptabschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-tableinfo"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mtr" substitutionGroup="ptabschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-align"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mlabeledtr" substitutionGroup="ptabschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-align"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mtd" substitutionGroup="ptabschema-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-align"/>
               <xsd:attributeGroup ref="att-spans"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Empty presentation layout schemata -->

   <xsd:element name="peschema-elt" abstract="true" substitutionGroup="PresInCont"/>

   <xsd:element name="maligngroup" substitutionGroup="peschema-elt">
      <xsd:complexType>
         <xsd:attributeGroup ref="MATHML.Common.attrib"/>
         <xsd:attribute name="groupalign" type="xsd:string" use="optional"/>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="malignmark" substitutionGroup="peschema-elt">
      <xsd:complexType>
         <xsd:attributeGroup ref="att-edge"/>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="mglyph">
      <xsd:complexType>
         <xsd:attribute name="alt" type="xsd:string" use="optional"/>
         <xsd:attribute name="fontfamily" type="fontfamily-type" use="optional"/>
         <xsd:attribute name="index" type="xsd:integer" use="optional"/>
      </xsd:complexType>
   </xsd:element>

   <!-- Presentation action schemata -->

   <xsd:element name="pactions-elt" abstract="true" substitutionGroup="PresInCont"/>

   <xsd:element name="maction" substitutionGroup="pactions-elt">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="PresExpression">
               <xsd:attributeGroup ref="att-actiontypeselection"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Content element set  ........................................ -->

   <!-- Attribute definitions -->

   <xsd:attributeGroup name="att-definitionInfo">
      <xsd:attribute name="definitionURL" type="xsd:string" use="optional"/><!--  use='default' value=''/> -->
      <xsd:attribute name="encoding" type="xsd:string"/> 
   </xsd:attributeGroup>

   <xsd:attributeGroup name="att-type">
      <xsd:attribute name="type" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <!-- Content -->

   <xsd:element name="Content" abstract="true"/>

   <xsd:element name="SharedContent" abstract="true" substitutionGroup="Content"/>

   <!-- Content elements: leaf nodes -->

   <xsd:element name="ctoken" abstract="true" substitutionGroup="SharedContent"/>

   <xsd:complexType name="ctokenType"> <!-- mixed='true'> -->
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      <xsd:attributeGroup ref="att-definitionInfo"/>
      <xsd:attributeGroup ref="att-type"/>
   </xsd:complexType>

   <xsd:element name="csymbol" substitutionGroup="ctoken">
      <xsd:complexType mixed="true">
         <xsd:complexContent mixed="true">
            <xsd:extension base="ctokenType">
               <xsd:choice minOccurs="0" maxOccurs="unbounded">
                  <xsd:element ref="mglyph"/>
                  <xsd:element ref="PresInCont"/>
               </xsd:choice>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="ci" substitutionGroup="ctoken">
      <xsd:complexType mixed="true">
         <xsd:complexContent mixed="true">
            <xsd:extension base="ctokenType">
               <xsd:choice minOccurs="0" maxOccurs="unbounded">
                  <xsd:element ref="mglyph"/>
                  <xsd:element ref="PresInCont"/>
               </xsd:choice>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="cn" substitutionGroup="ctoken">
      <xsd:complexType mixed="true">
         <xsd:complexContent mixed="true">
            <xsd:extension base="ctokenType">
               <xsd:choice minOccurs="0" maxOccurs="unbounded">
                  <xsd:element ref="mglyph"/>
                  <xsd:element ref="PresInCont"/>
                  <xsd:element ref="sep"/>
               </xsd:choice>
               <xsd:attribute name="base" type="xsd:string" default="10"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Content elements: specials -->

   <xsd:element name="cspecial" abstract="true" substitutionGroup="SharedContent"/>

   <xsd:element name="apply" type="ContentExpression" substitutionGroup="cspecial"/>

   <xsd:element name="reln" type="ContentExpression" substitutionGroup="cspecial"/>

   <xsd:element name="lambda" type="ContentExpression" substitutionGroup="cspecial"/>

   <!-- Content elements: others -->

   <xsd:element name="cother" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="condition" type="ContentExpression" substitutionGroup="cother"/>

   <xsd:element name="declare" substitutionGroup="cother">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attributeGroup ref="att-type"/>
               <xsd:attribute name="scope" type="xsd:string" default="local"/>
               <xsd:attribute name="nargs" type="xsd:string" default="1"/>
               <xsd:attribute name="occurrence" type="xsd:string" default="function-model"/>
               <xsd:attributeGroup ref="att-definitionInfo"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="sep" substitutionGroup="cother">
      <xsd:complexType/>
   </xsd:element>

   <!-- Content elements: semantic mapping -->

   <xsd:element name="csemantics" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="semantics" substitutionGroup="csemantics">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attributeGroup ref="att-definitionInfo"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="annotation" substitutionGroup="csemantics">
      <xsd:complexType mixed="true">
         <xsd:attributeGroup ref="MATHML.Common.attrib"/>
         <xsd:attribute name="encoding" type="xsd:string"/>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="annotation-xml" substitutionGroup="csemantics">
      <xsd:complexType>
         <xsd:sequence minOccurs="0" maxOccurs="unbounded">
            <xsd:any/>
         </xsd:sequence>
         <xsd:attributeGroup ref="MATHML.Common.attrib"/>
         <xsd:attribute name="encoding" type="xsd:string"/>
      </xsd:complexType>
   </xsd:element>

   <!-- Content elements: constructors -->

   <xsd:element name="cconstructor" abstract="true" substitutionGroup="SharedContent"/>

   <xsd:element name="interval" substitutionGroup="cconstructor">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attribute name="closure" type="xsd:string" default="closed"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="list" substitutionGroup="cconstructor">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attribute name="order" type="xsd:string" default="numeric"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="matrix" type="ContentExpression" substitutionGroup="cconstructor"/>

   <xsd:element name="matrixrow" type="ContentExpression" substitutionGroup="cconstructor"/>

   <xsd:element name="set" substitutionGroup="cconstructor">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attributeGroup ref="att-type"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="vector" type="ContentExpression" substitutionGroup="cconstructor"/>

   <xsd:element name="piecewise" substitutionGroup="cconstructor">
      <xsd:complexType>
         <xsd:sequence>
            <xsd:element ref="piece" minOccurs="0" maxOccurs="unbounded"/>
            <xsd:element ref="otherwise" minOccurs="0"/>
         </xsd:sequence>
         <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="piece" type="ContentExpression"/>

   <xsd:element name="otherwise" type="ContentExpression"/>

   <!-- Content elements: symbols -->

   <xsd:element name="c0ary" abstract="true" substitutionGroup="SharedContent"/>
   <xsd:complexType name="operatorType">
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      <xsd:attributeGroup ref="att-definitionInfo"/>
   </xsd:complexType>

   <xsd:element name="integers" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="reals" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="rationals" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="naturalnumbers" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="complexes" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="primes" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="exponentiale" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="imaginaryi" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="notanumber" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="true" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="false" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="emptyset" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="pi" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="eulergamma" type="operatorType" substitutionGroup="c0ary"/>

   <xsd:element name="infinity" type="operatorType" substitutionGroup="c0ary"/>

   <!-- Operator groups -->

   <xsd:element name="cop1ary" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="cop2ary" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="copnary" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="copmisc" abstract="true" substitutionGroup="Content"/>

   <!-- Content elements: operators -->

   <xsd:element name="cfuncop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="inverse" type="operatorType" substitutionGroup="cfuncop1ary"/>

   <xsd:element name="ident" type="operatorType" substitutionGroup="cfuncop1ary"/>

   <xsd:element name="domain" type="operatorType" substitutionGroup="cfuncop1ary"/>

   <xsd:element name="codomain" type="operatorType" substitutionGroup="cfuncop1ary"/>

   <xsd:element name="image" type="operatorType" substitutionGroup="cfuncop1ary"/>

   <xsd:element name="cfuncopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="fn" substitutionGroup="cfuncopnary">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="ContentExpression">
               <xsd:attributeGroup ref="att-definitionInfo"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <xsd:element name="compose" type="operatorType" substitutionGroup="cfuncopnary"/>

   <xsd:element name="carithop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="abs" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="conjugate" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="exp" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="factorial" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="arg" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="real" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="imaginary" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="floor" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="ceiling" type="operatorType" substitutionGroup="carithop1ary"/>

   <xsd:element name="carithop1or2ary" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="minus" type="operatorType" substitutionGroup="carithop1or2ary"/>

   <xsd:element name="carithop2ary" abstract="true" substitutionGroup="cop2ary"/>

   <xsd:element name="quotient" type="operatorType" substitutionGroup="carithop2ary"/>

   <xsd:element name="divide" type="operatorType" substitutionGroup="carithop2ary"/>

   <xsd:element name="power" type="operatorType" substitutionGroup="carithop2ary"/>

   <xsd:element name="rem" type="operatorType" substitutionGroup="carithop2ary"/>

   <xsd:element name="carithopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="plus" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="times" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="max" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="min" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="gcd" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="lcm" type="operatorType" substitutionGroup="carithopnary"/>

   <xsd:element name="carithoproot" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="root" type="operatorType" substitutionGroup="carithoproot"/>

   <xsd:element name="clogicopquant" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="exists" type="operatorType" substitutionGroup="clogicopquant"/>

   <xsd:element name="forall" type="operatorType" substitutionGroup="clogicopquant"/>

   <xsd:element name="clogicopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="and" type="operatorType" substitutionGroup="clogicopnary"/>

   <xsd:element name="or" type="operatorType" substitutionGroup="clogicopnary"/>

   <xsd:element name="xor" type="operatorType" substitutionGroup="clogicopnary"/>

   <xsd:element name="clogicop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="not" type="operatorType" substitutionGroup="clogicop1ary"/>

   <xsd:element name="clogicop2ary" abstract="true" substitutionGroup="cop2ary"/>

   <xsd:element name="implies" type="operatorType" substitutionGroup="clogicop2ary"/>

   <xsd:element name="ccalcop" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="log" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="int" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="diff" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="partialdiff" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="divergence" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="grad" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="curl" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="laplacian" type="operatorType" substitutionGroup="ccalcop"/>

   <xsd:element name="ccalcop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="ln" type="operatorType" substitutionGroup="ccalcop1ary"/>

   <xsd:element name="csetop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="card" type="operatorType" substitutionGroup="csetop1ary"/>

   <xsd:element name="csetop2ary" abstract="true" substitutionGroup="cop2ary"/>

   <xsd:element name="setdiff" type="operatorType" substitutionGroup="csetop2ary"/>

   <xsd:element name="csetopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="union" type="operatorType" substitutionGroup="csetopnary"/>

   <xsd:element name="intersect" type="operatorType" substitutionGroup="csetopnary"/>

   <xsd:element name="cartesianproduct" type="operatorType" substitutionGroup="csetopnary"/>

   <xsd:element name="cseqop" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="sum" type="operatorType" substitutionGroup="cseqop"/>

   <xsd:element name="product" type="operatorType" substitutionGroup="cseqop"/>

   <xsd:element name="limit" type="operatorType" substitutionGroup="cseqop"/>

   <xsd:element name="ctrigop" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="sin" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="cos" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="tan" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="sec" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="csc" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="cot" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="sinh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="cosh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="tanh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="sech" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="csch" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="coth" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arcsin" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccos" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arctan" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccosh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccot" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccoth" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccsc" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arccsch" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arcsec" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arcsech" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arcsinh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="arctanh" type="operatorType" substitutionGroup="ctrigop"/>

   <xsd:element name="cstatopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="mean" type="operatorType" substitutionGroup="cstatopnary"/>

   <xsd:element name="sdev" type="operatorType" substitutionGroup="cstatopnary"/>

   <xsd:element name="variance" type="operatorType" substitutionGroup="cstatopnary"/>

   <xsd:element name="median" type="operatorType" substitutionGroup="cstatopnary"/>

   <xsd:element name="mode" type="operatorType" substitutionGroup="cstatopnary"/>

   <xsd:element name="cstatopmoment" abstract="true" substitutionGroup="copmisc"/>

   <xsd:element name="moment" type="operatorType" substitutionGroup="cstatopmoment"/>

   <xsd:element name="clalgop1ary" abstract="true" substitutionGroup="cop1ary"/>

   <xsd:element name="determinant" type="operatorType" substitutionGroup="clalgop1ary"/>

   <xsd:element name="transpose" type="operatorType" substitutionGroup="clalgop1ary"/>

   <xsd:element name="clalgop2ary" abstract="true" substitutionGroup="cop2ary"/>

   <xsd:element name="vectorproduct" type="operatorType" substitutionGroup="clalgop2ary"/>

   <xsd:element name="scalarproduct" type="operatorType" substitutionGroup="clalgop2ary"/>

   <xsd:element name="outerproduct" type="operatorType" substitutionGroup="clalgop2ary"/>

   <xsd:element name="clalgopnary" abstract="true" substitutionGroup="copnary"/>

   <xsd:element name="selector" type="operatorType" substitutionGroup="clalgopnary"/>

   <!-- Relation groups -->

   <xsd:element name="crel2ary" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="crelnary" abstract="true" substitutionGroup="Content"/>

   <!-- Content elements: relations -->

   <xsd:element name="cgenrel2ary" abstract="true" substitutionGroup="crel2ary"/>

   <xsd:element name="neq" type="operatorType" substitutionGroup="cgenrel2ary"/>

   <xsd:element name="factorof" type="operatorType" substitutionGroup="cgenrel2ary"/>

   <xsd:element name="cgenrelnary" abstract="true" substitutionGroup="crelnary"/>

   <xsd:element name="eq" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="leq" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="lt" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="geq" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="gt" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="equivalent" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="approx" type="operatorType" substitutionGroup="cgenrelnary"/>

   <xsd:element name="csetrel2ary" abstract="true" substitutionGroup="crel2ary"/>

   <xsd:element name="in" type="operatorType" substitutionGroup="csetrel2ary"/>

   <xsd:element name="notin" type="operatorType" substitutionGroup="csetrel2ary"/>

   <xsd:element name="notsubset" type="operatorType" substitutionGroup="csetrel2ary"/>

   <xsd:element name="notprsubset" type="operatorType" substitutionGroup="csetrel2ary"/>

   <xsd:element name="csetrelnary" abstract="true" substitutionGroup="crelnary"/>

   <xsd:element name="subset" type="operatorType" substitutionGroup="csetrelnary"/>

   <xsd:element name="prsubset" type="operatorType" substitutionGroup="csetrelnary"/>

   <xsd:element name="cseqrel2ary" abstract="true" substitutionGroup="crel2ary"/>

   <xsd:element name="tendsto" substitutionGroup="cseqrel2ary">
      <xsd:complexType>
         <xsd:complexContent>
            <xsd:extension base="operatorType">
               <xsd:attributeGroup ref="att-type"/>
            </xsd:extension>
         </xsd:complexContent>
      </xsd:complexType>
   </xsd:element>

   <!-- Content elements: quantifiers -->

   <xsd:element name="cquantifier" abstract="true" substitutionGroup="Content"/>

   <xsd:element name="lowlimit" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="uplimit" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="bvar" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="degree" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="logbase" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="momentabout" type="ContentExpression" substitutionGroup="cquantifier"/>

   <xsd:element name="domainofapplication" type="ContentExpression" substitutionGroup="cquantifier"/>

   <!-- Content constructs for substitution in presentation structures -->

   <xsd:group name="ContInPres">
      <xsd:choice>
         <xsd:element ref="SharedContent"/>
         <xsd:element ref="fn"/>
         <xsd:element ref="semantics"/>
         <xsd:element ref="declare"/>
      </xsd:choice>
   </xsd:group>

   <!-- Recursive definition for content of expressions. Include
     presentation constructs at lowest level so presentation
     layout schemata hold presentation or content elements.
     Include content constructs at lowest level so content
     elements hold PCDATA or presentation elements at leaf
     level (for permitted substitutable elements in context)
    -->
   <xsd:complexType name="ContentExpression">
      <xsd:choice minOccurs="0" maxOccurs="unbounded">
         <xsd:element ref="Content"/>
         <xsd:element ref="PresInCont"/>
      </xsd:choice>
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
   </xsd:complexType>

   <xsd:complexType name="PresExpression">
      <xsd:choice minOccurs="0" maxOccurs="unbounded">
         <xsd:element ref="Presentation"/>
         <!-- Next 4 represent ContInPres -->
         <xsd:group ref="ContInPres"/>
         <!--     <xsd:element ref='SharedContent'/>  -->
         <!--     <xsd:element ref='semantics'/> -->
         <!--     <xsd:element ref='declare'/> -->
         <!--     <xsd:element ref='fn'/> -->
      </xsd:choice>
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
   </xsd:complexType>

   <xsd:complexType name="MathExpression">
      <xsd:choice minOccurs="0" maxOccurs="unbounded">
         <xsd:element ref="PresInCont"/>
         <!-- Next 4 represent ContInPres -->
         <xsd:group ref="ContInPres"/>
         <!--      <xsd:element ref='SharedContent'/> -->
         <!--      <xsd:element ref='fn'/> -->
         <!--      <xsd:element ref='semantics'/> -->
         <!--      <xsd:element ref='declare'/> -->
      </xsd:choice>
      <xsd:attributeGroup ref="att-topinfo"/>
      <xsd:attributeGroup ref="att-browif"/>
   </xsd:complexType>

   <!-- Browser interface definition  ............................... -->

   <!-- Attributes for top-level element "math" -->

   <xsd:attributeGroup name="att-topinfo">
      <xsd:attributeGroup ref="MATHML.Common.attrib"/>
      <xsd:attribute name="macros" type="xsd:string" use="optional"/>
      <xsd:attribute name="mode" type="xsd:string" use="optional"/>
      <xsd:attribute name="display" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <!-- Attributes for browser interface element -->

   <xsd:attributeGroup name="att-browif">
      <xsd:attributeGroup ref="att-type"/>
      <xsd:attribute name="name" type="xsd:string" use="optional"/>
      <xsd:attribute name="width" type="space-type" use="optional"/>
      <xsd:attribute name="height" type="vsize-type" use="optional"/>
      <xsd:attribute name="baseline" type="xsd:string" use="optional"/>
      <xsd:attribute name="overflow" default="scroll">
         <xsd:simpleType>
            <xsd:restriction base="xsd:string">
               <xsd:enumeration value="scroll"/>
               <xsd:enumeration value="elide"/>
               <xsd:enumeration value="truncate"/>
               <xsd:enumeration value="scale"/>
            </xsd:restriction>
         </xsd:simpleType>
      </xsd:attribute>
      <xsd:attribute name="altimg" type="xsd:string" use="optional"/>
      <xsd:attribute name="alttext" type="xsd:string" use="optional"/>
   </xsd:attributeGroup>

   <!-- The top-level element "math" contains MathML encoded
       mathematics. The "math" element has the browser info
       attributes iff it is also the browser interface element.
      -->
   <xsd:element name="math" type="MathExpression"/>
</xsd:schema>