# Symbol of Natural numbers

I have been commonly using $\mathbb {N}$ and $\mathbb {Z}^{+}$ to denote natural numbers. Recently I have come across on some questions the symbol $\mathbb {I}$. I have checked various websites and have not found anything to do with the I symbol. Is it a proper symbol? I will be glad to know. Probably, it is used elsewhere in the world and I am unaware. Note by Joel Tan
6 years, 2 months ago

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Nope, not as far as I know. I try to refrain from using $\mathbb{N}$ unless it looks super ugly otherwise, to avoid any confusion. I take $\mathbb{N} = \mathbb{Z}^{+} \cup \lbrace 0 \rbrace$ as per the Peano axioms.

- 6 years, 2 months ago

The formal definition of natural numbers exclude 0.

- 6 years, 2 months ago

- 6 years, 2 months ago

- 6 years, 2 months ago

I've not see $\mathbb{I}$ for ideals. They are often just $I$ or $J$.

Staff - 6 years, 2 months ago

Oh yeah, it does look different, I thought it was the normal capital I.

- 6 years, 2 months ago

$\mathbb{I}$ is used in India along with $mathbb{N}$ and $\mathbb{Z}^{+}$ to represent Natural numbers .

But as far as official use is considered , $mathbb{N}$ would be my choice .

- 6 years, 2 months ago