+///
+MathMLStream & operator<<(MathMLStream &, MathInset const *);
+///
+MathMLStream & operator<<(MathMLStream &, MathArray const &);
+///
+MathMLStream & operator<<(MathMLStream &, char const *);
+///
+MathMLStream & operator<<(MathMLStream &, char);
+///
+MathMLStream & operator<<(MathMLStream &, MTag const &);
+///
+MathMLStream & operator<<(MathMLStream &, ETag const &);
+