How to pronounce the first letter of mathematics in the first year of set function?

N: non-negative integer set or natural number set {0, 1, 2, 3, ...}

N* or N+: positive integer set {1, 2,3, ...}

Z: integer set {…,-1, 0, 1, …}

P: a group of prime numbers

Q: Rational number set

Q+: Set of Positive Rational Numbers

Q-: set of negative rational numbers

R: real number set

R+: positive real number set

R-: negative real number set

C: complex set

: empty set (a set without any elements is called an empty set)

U: complete set (including all the elements discussed in the question)

As for pronunciation, you should follow the letters. Read as an empty set.

Please adopt it. Thank you.