Update index.html

correction of copy-paste error

Author: doerthe

spec/index.html

@@ -280,7 +280,7 @@ <h2>Notation and Terminology</h2>
     For RDF terms t, x and y, we define the  <dfn>substitution mapping</dfn>, t[x/y] inductively as follows: 
     <ol>
     <li> if  t=x, then t[x/y]=y; </li>
-    <li> if t = (s,p,o) and t &ne; x, then t[x/y]= (s[x/y], p[x/y], o[x/y]=y);</li>
+    <li> if t = (s,p,o) and t &ne; x, then t[x/y]= (s[x/y], p[x/y], o[x/y]);</li>
     <li> else, t[x/y]=t. </li>
   </ol>
     For each triple (s,p,o), we set (s,p,o)[x/y]= (s[x/y],p[x/y],o[x/y]). For each graph G, we obtain G[x/y] by applying [x/y] to each triple t in G.