A statement in a book of analysis I have says: (Q,+, .) is a commutative ring with an identity element. I assume by its notation (Q,+,.) is a tuple.(correct?) There are several questions that come to mind: 1. Why is there an order between Q,+ and . ? 2. As far as I know, a tuple is an element of a cartesian product of sets. A ring [itex]\subset[/itex] set. So in other words the book says that the tuple (Q,+,.) is a set. How can a tuple be a set? Isn't that like saying that an element is a set? 3. Of what is + an element of? The set of numeral operators? If so, why can't I find it on the web?