Set notation

∈

is an element of

∉

is not an element of

⊆

is a subset of

⊂

is a proper subset of

{x1, x2, …}

the set with elements x1, x2, …

{x : …}

the set of all x such that

n(A)

the number of elements in set A

∅

the empty set

ε

the universal set

A′

the complement of the set A

ℕ

the set of natural numbers, {1, 2, 3, …}

ℤ

the set of integers, {0, ±1, ±2, ±3, …}

ℤ+

the set of positive integers, {1, 2, 3, …}

ℤ0 +

the set of non-negative integers, {0, 1, 2, 3, …}

ℝ

the set of real numbers

ℚ

the set of rational numbers, : , p p q q + ∈ ∈

∪

union

∩

intersection

(x, y) the ordered pair x, y

[a, b] the closed interval {x ∈ ℝ: a ≤ x ≤ b}

[a, b) the interval {x ∈ ℝ: a ≤ x < b}

(a, b] the interval {{x ∈ ℝ: a < x ≤ b}

(a, b) the open interval {x ∈ ℝ: a < x < b}