OK, I went and looked at the standard and it seems like they're thought about this: they allow input as either ∫(x²/2) or ∫(x^2/2) but they apparently output as ∫(x^2/2) because it's more general and editable, like if you wanted to change the exponent to something that didn't have a predefined Unicode superscript.
Thus assume only + - and * / are unambiguous, everything else be explicit about ordering.
EG: ∫((x^2)/2)
Maybe it could be integrated into the Unicode shaper (HarfBuzz/Uniscribe/AAT) with a language code for "maths".
Unfortunately not! I am wondering if I should make requests to the Windows team internally, the Managed wrapper class they ship has the math features compiled out. :( I'm in Office, where we use an internal UWP safe C++ version of Rich Edit. We bundle it with our AppX and load it up like any other C++ DLL.
Please post over on https://wpdev.uservoice.com/ and get others to upvote! If internal and external asks line up, it becomes much easier to argue in favor of doing a feature.
Microsoft Office has two internal math formats, one of them is Ecma Math[0], the other the other is the "Unicode Nearly Plain-Text Encoding of Mathematics"[1], it is a Unicode standard and uses only Unicode standard characters. It has the unfortunate property of being hard to type on its own (the integral character isn't on most people's keyboards), but it is pretty easy to read as just plain text. If you copy an equation out of Word you'll get something like this: ∫(x^2/2)
[0] https://blogs.msdn.microsoft.com/murrays/2006/10/06/mathml-a...
[1] http://unicode.org/notes/tn28/UTN28-PlainTextMath-v3.pdf
Disclaimer: I work @Microsoft improving on some math features, and we are the main implementors of the spec. Which makes me sad, since it is an open spec and it is really powerful!