PreTeXt uses the well-known LaTeX syntax for mathematics. One fundamental reason for this choice is that the MathJax 1 Javascript library is so capable at rendering LaTeX inside of an HTML web page. Of course, it is not hard to render LaTeX syntax inside of LaTeX output! But what about output formats that are not processed by LaTeX or Javascript, such as EPUB or braille? That is where running MathJax offline (locally) comes into play.
