Update spec/index.html

Co-authored-by: Ted Thibodeau Jr <[email protected]>

Author: doerthe

spec/index.html

@@ -277,7 +277,8 @@ <h2>Notation and Terminology</h2>
 
 
   <p>
-    For RDF terms t, x and y, we define the  <dfn>substitution mapping</dfn>, t[x/y] inductively as follows: 
+    For RDF terms t, x, and y, we define the <dfn>substitution mapping</dfn> t[x/y] inductively, as follows:
+  </p>
     <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]);</li>