$\mathbb{N}$ names (the counting numbers).

Read "$\mathbb{N}$ names (the (natural number) set)."

(1)

(the natural numbers) are the numbers we count things with. $\mathbb{N}$ is a synonym for (the natural numbers). Zero is not among the natural numbers, as it represents the absence of a number. The curly brackets { and } in the notation are used to contain a distinct set of symbols, and the commas (which are optional) are used to help distinguish the symbols thus contained. The symbols $1$, $2$ and $3$ represent the counting numbers. The symbol ... represents the action of continuing to count forever.

(1)