changes the presentation of the 'multiplicity' function, as discussed…

… in #110 (comment)

spec/index.html

@@ -8965,10 +8965,10 @@ <h3>Basic Graph Patterns</h3>
         <div class="defn">
           <p><b>Definition: <span id="defn_Multiplicity">Multiplicity</span></b></p>
           <p>Given a multiset&nbsp;<var>Ω</var> of solution mappings and a solution
-            mapping&nbsp;<var>μ</var>, we write <var>multiplicity<sup><var>Ω</var></sup></var>(<var>μ</var>)
+            mapping&nbsp;<var>μ</var>, we write <var>multiplicity</var>(<var>μ</var>&nbsp;|&nbsp;<var>Ω</var>)
             to denote the number of times <var>μ</var> appears in <var>Ω</var>.</p>
           <p>Similarly, given a solution sequence&nbsp;<var>Ψ</var> and a solution
-            mapping&nbsp;<var>μ</var>, we write <var>multiplicity<sup><var>Ψ</var></sup></var>(<var>μ</var>)
+            mapping&nbsp;<var>μ</var>, we write <var>multiplicity</var>(<var>μ</var>&nbsp;|&nbsp;<var>Ψ</var>)
             to denote the number of times <var>μ</var> appears in <var>Ψ</var>.</p>
         </div>
         <section id="BGPsparql">
@@ -9262,8 +9262,8 @@ <h3>SPARQL Algebra</h3>
           <p>Let Ω be a multiset of solution mappings and expr be an expression. We define:</p>
           <p>Filter(expr, Ω) = { μ | μ in Ω and expr(μ) is an expression that has an
             effective boolean value of true }</p>
-          <p><a href="#defn_Multiplicity">multiplicity</a><sup>Filter(expr, Ω)</sup>(μ)
-            = <a href="#defn_Multiplicity">multiplicity</a><sup>Ω</sup>(μ)</p>
+          <p><a href="#defn_Multiplicity">multiplicity</a>( μ | Filter(expr, Ω) )
+            = <a href="#defn_Multiplicity">multiplicity</a>( μ | Ω )</p>
           <blockquote>
             Note that evaluating an <code>exists(pattern)</code> expression uses the dataset and
             active graph, D(G). See the <a href="#defn_evalFilter">evaluation of filter</a>.