Re: How to read mathematics

John Jones schrieb:
"The set of all rational numbers is countable" - grammatically, the count refers to the set and not to all rational numbers.

So if you want to actually count it, then that count is one, one set. You see, by expressing a scenario in which there is a count, then we can see what it is that is counted.

Countable is a technical term, which means(*) that
the set can be injectively mapped to the natural
numbers. So the following sets are countable:

{1,2,3}
the even numbers
the rational numbers

Please read a decent introductory math book.

(*) The term is defined as such. You cannot
draw the definition from your common knowledge.
It is define in some books somewhere.

Its a "technical" term of math.
.