Martin Escardo on Nostr: I think the essence of the problem is that students (and sometimes teachers) are not ...

I think the essence of the problem is that students (and sometimes teachers) are not told what real numbers are, explicitly by a construction or axiomatically by a list of properties they are expected to obey.

If the thing you are discussing is not well defined, then one can expect any answer to all sort of questions, including the one under discussion.