Sets

Question 1

Set

Answer 1

defn - a collection of objects and a way of deciding which objects belong in the collection.

Question 2

Members/elements of a set

Answer 2

Objects that are in the set

Question 3

Meaning of x ∈ S

Answer 3

x belongs to the set S

Question 4

Meaning of x ∉ S

Answer 4

x does not belong to the set S

Question 5

Equal sets

Answer 5

defn - two sets are equal if they have exactly the same elements

Question 6

The empty set

Answer 6

the set containing no elements

Question 7

How can you describe sets?

Answer 7

1. Listing the elements. Large or infinite sets can be written this way using ‘…’
2. Specifying a defining property.
   a. {all things with a specific property}
   b. {x | x has a particular property}
   c. {x ∈ U | x has a particular property}