As others have mentioned, there is no standard. The closest thing would probably be A history of mathematical notations by Florian Cajori (2 volumes, 1928), bu

As others have mentioned, there is no standard. The closest thing would probably be A history of mathematical notations by Florian Cajori (2 volumes, 1928), but that illustrates how diverse, inconsistent and downright weird the notation can be. It's just as well that the precision of mathematics does not depend on it.