It seems tempting to have a single unambiguous notation for mathematics. But
In constructing such a language, one will quickly realize that doing mathematics becomes an intensely arduous task.
This is not unlike recent discussions about the conlang Ithkuil on HN.
For better or for worse, math notation has for the most part been optimized for writing on paper or a blackboard, using context to eliminate "inessential details". Local edits are generally easy, and pieces of notation are not always so tightly coupled. (For example, we can put a "for all x" at a distance from some equation.)
Have you ever attempted to write Lisp on a blackboard, then needing to insert an expression in the middle? It's extremely difficult because you have to perform a quadratic process (erasing everything after and reindenting) to make the Lisp readable. At least this is what I've noticed in interviews. You can sometimes patch your Lisp forms with lines and arrows, but it's the quickest way to get spaghetti on your blackboard.
RPN is similarly useless for the task. RPN is exceedingly easy to write, but not so easy to read. Also, higher level mathematics becomes unwieldy in RPN.
Sussman and Wisdom in their book "Structure and Interpretation of Classical Mechanics" did take a different approach to math notation in order to make it unambiguous for that relatively small sub field. It looks like regular math notation but written in such a way to make things more easily computable. I'd say they were successful, though their work would be difficult to generalize.
