The symbol $n$? Natural numbers?

This might seem like a very basic question, but it keeps bugging me.

Does the symbol $n$ mean the set of natural numbers $\mathbb{N}$ shortened to $n$ to ease writing?

Or is it rather the positive and negative quantities (known as integers ($\mathbb{Z}$)

Or real numbers $\mathbb{R}$?

1 Answer

The set $\mathbb{N}$ is the natural numbers. But usually in the context of number theory when one writes $n$, one means a particular natural number. For example, $n$ could be $5$ or $12$ or $1$ or $1,234,453,564,234,134,179,200$. But they would usually not use it to denote any integer and certainly not a real number.

In any case, what the variable $n$ is being used for should always be stated somewhere in the text whenever it is used, so search for what they have declared it to represent.