In the context of this paper, we are talking about floating point arithmetic used by mathematicians working in Mathematica. I disagree with you on these points.

In the context of this paper, we are talking about floating point arithmetic used by mathematicians working in Mathematica. I disagree with you on these points. > you need to sort them first Yes, but only if there are quite a lot of them and the partial sums are large relative to the result. Not really an issue usually. > The inability to represent 0.1 Many mathematical conjectures apply for arbitrary real numbers. The nearest floating point number to 0.1 is a real number, and it's not really an issue for mathematics that it's not exactly 0.1. > single-precision might not be enough These are mathematicians working in Mathematica, which has an arbitrary-precision floating-point type. They don't have to come anywhere near single precision floats. > if you are going to represent exchange prices You can use integers. Floating-point arithmetic isn't really great here because it makes the wrong kinds of accuracy guarantees. > prime number work Primes numbers are all integers. It would be a bit silly to represent integers with floating-point numbers.