Sets and Functions Flashcards
1
Q
A = B
A
x | x ∈ A <=> x ∈ B
2
Q
A U B
A
x| x ∈ A v x ∈ B
3
Q
A ∩ B
A
x| x ∈ A ^ x ∈ B
4
Q
A - B
A
x| x ∈ A ^ x ∉ B
5
Q
|A U B|
A
|A| + |B| - |A ∩ B|
6
Q
|A - B|
A
|A| - |A ∩ B|
7
Q
A complement
A
x | x ∈ U ^ x ∉ A
8
Q
A ⊆ B
A
x | x ∈ A -> x ∈ B
9
Q
A ⊂ B
A
x | x ∈ A -> x ∈ B ^ ∃x x ∈ B ^ x ∉ A
10
Q
Injective (one to one)
A
∀x ∀y, x ≠ y -> f(x) ≠ f(y)
each element of the codomain is mapped to by at most one element of the domain
11
Q
Surjective (onto)
A
codomain = range
each element of the codomain is mapped to by at least one element of the domain
