Reduce XML validation errors caused by inappropriate usage of ( and )

Author: Dani-Hub

xml/issue4212.xml

@@ -26,9 +26,9 @@ This allows us to state the result precisely, and makes it clear how each round
 values of the previous rounds.
 <p/>
 It seems convenient to change the round counter <math><mi>q</mi></math> to be 1-based (and 
-<math><msup><mi>X</mi><mrow>(<mn>0</mn>)</mrow></msup></math>
+<math><msup><mi>X</mi><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow></msup></math>
 is an alias for the initial value, <math><mi>X</mi></math>), so that the final result is 
-<math><msup><mi>X</mi><mrow>(<mi>r</mi>)</mrow></msup></math>.
+<math><msup><mi>X</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow></msup></math>.
 </p>
 </discussion>