<?xml version="1.0" encoding="UTF-8"?>
<!-- Minimal SI schema stub for offline validation: ONLY defines real and realListXMLList elements used indirectly. -->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           targetNamespace="https://ptb.de/si"
           xmlns:si="https://ptb.de/si"
           elementFormDefault="qualified">
  <xs:element name="real" type="si:realType"/>
  <xs:element name="hybrid" type="si:hybridType"/>
  <xs:element name="complex" type="si:complexType"/>
  <xs:element name="constant" type="si:constantType"/>
  <xs:element name="list" type="si:listType"/>
  <xs:complexType name="realType">
    <xs:sequence>
      <xs:element name="label" type="xs:string" minOccurs="0"/>
      <xs:element name="quantityTypeQUDT" type="xs:string" minOccurs="0"/>
      <xs:element name="value" type="xs:double"/>
      <xs:element name="unit" type="xs:string"/>
      <xs:element name="measurementUncertaintyUnivariate" minOccurs="0">
        <xs:complexType>
          <xs:sequence>
            <xs:element name="expandedMU" minOccurs="0">
              <xs:complexType>
                <xs:sequence>
                  <xs:element name="valueExpandedMU" type="xs:double" minOccurs="0"/>
                  <xs:element name="coverageFactor" type="xs:double" minOccurs="0"/>
                  <xs:element name="coverageProbability" type="xs:double" minOccurs="0"/>
                  <xs:element name="distribution" type="xs:string" minOccurs="0"/>
                </xs:sequence>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
    </xs:sequence>
  </xs:complexType>

  <!-- Alias used by DCC -->
  <xs:complexType name="realQuantityType">
    <xs:sequence>
      <xs:element name="label" type="xs:string" minOccurs="0"/>
      <xs:element name="quantityTypeQUDT" type="xs:string" minOccurs="0"/>
      <xs:element name="value" type="xs:double"/>
      <xs:element name="unit" type="xs:string"/>
      <xs:element name="measurementUncertaintyUnivariate" minOccurs="0">
        <xs:complexType>
          <xs:sequence>
            <xs:element name="expandedMU" minOccurs="0">
              <xs:complexType>
                <xs:sequence>
                  <xs:element name="valueExpandedMU" type="xs:double" minOccurs="0"/>
                  <xs:element name="coverageFactor" type="xs:double" minOccurs="0"/>
                  <xs:element name="coverageProbability" type="xs:double" minOccurs="0"/>
                  <xs:element name="distribution" type="xs:string" minOccurs="0"/>
                </xs:sequence>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
    </xs:sequence>
  </xs:complexType>

  <!-- Type used by DCC: realListXMLListType -->
  <xs:complexType name="realListXMLListType">
    <xs:sequence>
      <xs:element name="valueXMLList" type="xs:double" maxOccurs="unbounded"/>
      <xs:element name="unitXMLList" type="xs:string" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>
  <xs:element name="realListXMLList" type="si:realListXMLListType"/>
  <!-- Additional minimal complex types inside same schema -->
  <xs:complexType name="hybridType"><xs:sequence/></xs:complexType>
  <xs:complexType name="complexType"><xs:sequence/></xs:complexType>
  <xs:complexType name="constantType"><xs:sequence/></xs:complexType>
  <xs:element name="complexListXMLList" type="si:complexListType"/>
  <xs:complexType name="complexListType"><xs:sequence/></xs:complexType>
  <xs:complexType name="listType"><xs:sequence/></xs:complexType>
</xs:schema>
