R: set of real numbers (including rational numbers and irrational numbers); Z: integer set {…,-1, 0, 1, …}; N represents a non-negative integer set; Q stands for rational number set.

Other signs:

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

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

Q+: Set of Positive Rational Numbers

Q-: set of negative rational numbers

R+: positive real number set

R-: negative real number set

C: complex set

: empty set (a set without any elements)

Extended data:

Set, for short, is a basic concept in mathematics and the main research object of set theory. The basic theory of set theory was founded in19th century, and the simplest statement about set is the definition in naive set theory (the most primitive set theory).

That is, a set is a "definite pile of things", and the "things" in the set are called elements. A modern set is usually defined as a whole consisting of one or more definite elements.

References:

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