MathML

MathML is about encoding the structure of mathematical expressions so that they can be displayed, manipulated and shared over the World Wide Web. A carefully encoded MathML expression can be evaluated in a computer algebra system, rendered in a Web browser, edited in your word processor, and printed on your laser printer. Mathematical software vendors are adding MathML support at a rapid pace, and MathML is fast becoming the lingua franca of scientific publication on the Web.

http://www.snipsnap.org/space/MathML