Reader for AsciiMath (asciimath.org): sum_(i=1)^n i^2 = (n(n+1)(2n+1))/6. It builds the same tree of
meaning as the LaTeX reader. Symbols are given by their LaTeX spelling and read by the LaTeX reader,
so both notations draw and speak a symbol the same way.
Reader for presentation MathML, the markup Word, Google Docs, MathType, LibreOffice and MathJax export.
It builds the same tree of meaning as the LaTeX reader, so layout, speech and text are shared.
Content MathML (<apply>, <ci>) is meaning without a drawing: it is outside this reader.