added true case to recursion support

git-svn-id: http://acl2-books.googlecode.com/svn/branches/6.3@2133 303c5b2c-9740-0410-b014-fd8f9db7be32
number congruence thms

git-svn-id: http://acl2-books.googlecode.com/svn/branches/6.3@2134 303c5b2c-9740-0410-b014-fd8f9db7be32