title: RDF Data Cube uses property as object?
body: <p>as i read the <a href="http://www.w3.org/TR/vocab-data-cube/" rel="nofollow">RDF Data Cube Vocabulary</a> document, one thing confuses me: <code>MeasureProperties</code> (in the following example I use <code>eg:lifeExpectancy</code> are first defined as <strong>properties</strong>. however, when defining the data structure they are used as <strong>objects</strong>. is this allowed? please see the following example taken directly from the specification document.</p>
  
  <p>so, first the <code>MeasureProperty</code> itself gets defined as an <code>rdf:property</code>. see the following example of <code>eg:lifeExpectancy</code>:</p>
  
  <pre><code>eg:lifeExpectancy  a rdf:Property, qb:MeasureProperty;
      rdfs:label "life expectancy"@en;
      rdfs:subPropertyOf sdmx-measure:obsValue;
      rdfs:range xsd:decimal . 
  </code></pre>
  
  <p>later, this <code>MeasureProperty</code> is used to define a data structure:</p>
  
  <pre><code>eg:dsd-le a qb:DataStructureDefinition;
      # The dimensions
      [...]
      # The measure(s)
      qb:component [ qb:measure eg:lifeExpectancy];
      # The attributes
      [...]
  </code></pre>
  
  <p>as you can see <code>eg:lifeExpectancy</code> here is used as an <strong>object</strong>, which shouldn't be allowed, since it is a <strong>property</strong>?! or am I thinking wrong?</p>
  
  <p>later, when actually expressing the observations, <code>eg:lifeExpectancy</code> is us as a <strong>property</strong>:</p>
  
  <pre><code>eg:o1 a qb:Observation;
      qb:dataSet  eg:dataset-le1 ;
      eg:refArea                 ex-geo:newport_00pr ;                  
      sdmx-dimension:sex         sdmx-code:sex-M ;
      sdmx-attribute:unitMeasure &lt;http://dbpedia.org/resource/Year&gt; ;
      eg:lifeExpectancy          76.7 ;
      .
  </code></pre>
  
  <p>how is it possible/allowed to use <code>eg:lifeExpectancy</code>  as an object, as it is done in the <code>qb:DataStructureDefinition</code> above?</p>