Representations of uncomputable and uncountable sets
Occasionally I hear claims that uncountable and uncomputable sets cannot be represented on computers. More generally, there are all sorts of misguided opinions about representations of data on computers, especially infinite data of mathematical nature. Here is a quick tutorial on the matter whose main point is:
It is meaningless to discuss representations of a set by a datatype without also considering operations that we want to perform on the set.