MathML is probably better than LaTeX, but I'm lazy

There's a good overview of MathML provided by Wolfram. MathML interacts with Mathematica, both for import and export. 

"MathML comes in two types: Presentation MathML, which describes what an equation looks like, and Content MathML, which describes what an equation means. By default, MathJax works with Presentation MathML and offers an extension for Content MathML." 

There are online tools that enable conversion of LaTeX (mathematics) to Presentation MathML.

MathML is probably the better format to store data in the Physics Derivation Graph compared to Latex. However, Latex is more convenient for me as a data entry method.