Set Theory

Question 1

Intersection

Answer 1

The set of elements belonging to both A and B

Question 2

Power set

Answer 2

The set of all subsets of a set A

Question 3

Disjoint

Answer 3

If two sets have no elements in common

Question 4

Difference

Answer 4

The set of elements where x is an element in A but not in B; remove commonalities

Question 5

Symmetric difference

Answer 5

(A union B)-(A intersection B)

Question 6

Complement

Answer 6

The set of elements in the universal set not belonging to A

Question 7

Cartesian product

Answer 7

The set of all ordered pairs who’s first element is in A and who’s second element is in B (for AxB)

Question 8

Relation

Answer 8

Defined by letting xRy where x and y are in S

Question 9

Reflexive

Answer 9

If for each x in S, xRx is true

Question 10

Symmetric

Answer 10

If yRx is true whenever xRy is true

Question 11

Transitive

Answer 11

If xRz is true whenever xRy and yRz are both true

Question 12

Union

Answer 12

The set of elements belonging to one of A and B

Question 13

Equivalence relation

Answer 13

When a relation is reflexive, transitive and symmetric