My interpretation is that the OP is looking for rendering of markup into fancy, graphical depictions of equations and formulae. If instead the question is about simple substitutions of Unicode mathematical characters then @Rich has a nice answer.
vim is a text editor. It can display parallel, uniformly sized and spaced rows of Unicode characters and nothing more. Just like what you're reading now. The best you can do with markup languages is edit them and, possibly, launch an external command that renders them into a format that you'll need to read in an external viewer (e.g. browser, PDF viewer,
In fact, that's exactly what I do with
asciidoctor. I write my notes using AsciiDoc markup in
vim. I have
vim shortcuts to external commands that render the markup as HTML then launch/load my browser with that HTML.
(The next level of sophistication is to set up live preview. We put
vim and the viewer app side by side then use a file monitoring tool that upon seeing changes to the markup file renders and reloads the viewer automatically. That's as close to live editing of markup as you'll get with