In MathJax, users can set their math renderer to HTML-CSS, MathML and SVG. They seems affect fonts displayed. But what is the actual difference between them?
Note that fonts in pdf files are fixed, so they are invariable for different machines, i.e. are invariants of machine transformations. However fonts displayed by HTML-CSS relies on fonts used by our browser, hence are variable for machines. But are MathML and SVG also using local fonts?