sets Flashcards
1
Q
what is a set
A
an unordered set of elements without duplicates
2
Q
A ∪ B
A
union; combines two sets
3
Q
A ∩ B
A
intersection; elements that are in both A and B
4
Q
A ⊆ B
A
subset; when every element in A is in B
(super set is the other way round)
5
Q
A ⊂ B
A
proper subset; when every element in A is in B but they’re not equal (B has more elements)
6
Q
A ⊄ B
A
not a subset
7
Q
A − B
A
difference
8
Q
Ø
A
empty set ({})
9
Q
U
A
universal set; all possible values in the area of interest
10
Q
A×B
A
Cartesian product; everything in A should by but in an ordered pair with everything in B
11
Q
|A|
A
cardinality; the number of elements in the set
12
Q
∀
A
for all
13
Q
∃
A
there exists
14
Q
a ∈ A
A
a is an element of A
15
Q
disjoint sets
A
sets with no elements in common
