Mathjax is the seventh web system for LaTeX I am testing on this blog. TeX - by Donald Knuth - or LaTeX - with some help from Leslie Lamport - is the experts' standard to write mathematical expressions and formulae - and texts with lots of formulae. Most papers at arXiv.org are originally written in TeX or LaTeX.
We clearly cannot afford to reserve $...$ for the inline mathematics because this blog is full of the dollar signs which usually denote the U.S. currency. However, we may be getting ready for the default of the U.S. government so if you fairly replace one dollar by three dollars, things will be fine. For example, $$
Alternatively, you may use \