Unit 2: Sets, Logic,
Probability
2.1 Introduction to Sets
- A set is a collection of elements that all share a property.
- Sets are always labeled with capital letters.
- Elements exist within sets and always take lower case letters.
means ‘the union
of set A and set B’. If an element belongs to either set A or set B or
both, then it belongs in the union.
means ‘the intersection of set A and set B’. If an element belongs to set
A and set B at the same time, it belongs to the intersection.
means ‘x is an element of A’
means ‘set A is a subset
of set B’. It means the whole of
set A exists within set B.
refers to the
number of elements in set A
or 
both indicate disjoint sets. Disjoint sets have no elements in
common.- U is reserved for the Universal Set. U always contains all elements relevant to the context of the question.
refers to the compliment
of set A. contains all elements that are not in set A.- Sets can be finite or infinite. This refers to the number of elements in the set. If you can count the number of elements, the set is finite.
- Set
builder notation:
reads ‘the set of
all x such that x is an integer between -2 and 4,
inclusive’.
p. 19# 1-3
p. 69#1-5
p. 70# 1-12