Make sure that the comparator detect mismatched namespaces.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1524487 13f79535-47bb-0310-9956-ffa450edef68
Use italic for single letter variable in math expressions.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1524488 13f79535-47bb-0310-9956-ffa450edef68