On: A Spectre Is Haunting Unicode (2018)

[dnautics]

CHNPRQ and Z are the ones with actual canonical meaning:

- Complex

- Quaternion (H for Hamilton)

- Natural

- Prime

- Rational (Q for quotient)

- Real

- Zinteger

just kidding. i think Z stands for something in German.

[runarberg → dnautics]

I have also seen

- ℙ used to denote a probability distribution

- 𝔼[X] as the expected value of a random variable X

- 𝟙_S as an indicator function for a set S (which is denoted as a subscript)

- 𝕕 as the differential and integral operator denouncing which variable to integrate over 𝕕f/𝕕x f(x) or ∫ f(x) 𝕕x

[OscarCunningham → runarberg]

I've also seen 𝔸 for affine space, 𝔹 for the Booleans, 𝔽 for a field, 𝕂 for a field, 𝕆 for octonions and 𝕊 for surreals.

I think I've seen 𝕀 and 𝕚 for identity matrices and suchlike, and I'm sure 𝟘 also gets some use.

[pvg → dnautics]

Z for Zahlen, "numbers". "Zinteger" is an improvement, being more precise.

[_ph_ → dnautics]

N are the positive integers including zero, Z are all integers.

[dnautics → _ph_]

This is the math equivalent of tabs vs spaces

[Lvl999Noob → _ph_]

Isn't N just the positive integers and W the one with zero?

[a1369209993 → Lvl999Noob]

No, the positive intergers are Z⁺ (Z^+ / Z⁺). N is natural numbers aka nonnegative integers aka positive integers along with (not "including", since it isn't positive) zero.