SET: INTRODUCTIO

1. Week 1 online class
9/18/2021

3. SET

4. SET is a well-defined group of
objects, called elements, that
share a common characteristic.
For example, 3 of the objects
belong to the set of hat (ladies
hat, baseball cap, hard hat)

5. Set F is a SUBSET of set A if all
elements of F are also elements
of A. For example, the even
numbers 2, 4, and 12 all belong to
the set of whole numbers.
Therefore, the even numbers 2,
4, and 12 form a subset of the set
of whole numbers.

6. EXAMPLE:
A={English alphabet} n(A)=26
B={vowels} n(B)=5
Set B is subset of set A- true
Set A is subset of set B- false
EXAMPLE:
A={1,2,3,4,5,6,7,8,9,10} n(A)=10
B={0,2,4,6,8} n(B)=5
C={1,3,5,7,9}
B is subset of A-false

7. UNIVERSAL SET
U is the set that
contains all objects
under
consideration.

8. NULL SET  is an
empty set. The null
set is a subset of any
set.

9. CARDINALITY OF A
SET is the number of
elements contained in a
set.
n(A)- cardinality of set A

10. DIFFERENCE OF TWO
SETS.
Set A and set B. Denoted by
A-B. Is the set that contains
all elements of A not are not
in B.

11. EXAMPLE:
A={1,2,3,4,5,6,7,8,9,10}
B={0,2,4,6,8,9,10}
C={1,3,5}
A-B={1,3,5,7}
A-C={2,4,6,7,8,9,10}

14. b,c,d,f,g,h,j,k,l,m,n,p,q,r,s,t,v,w,x,y,z

18. A-B={c,o,n,a}

20. Do you have
questions?

21. Notations and
Symbols

22. 1.Uppercase letters will be
used to name sets and
lowercase letters will be used
to refer to any element of a set.
For example, let H be the set of
all objects that cover or protect
the head. We write:
H = {ladies hat, baseball cap, hard hat}

23. 2 methods of writing
elements of set.
1. Roster method – simply
listing elements contained
in a set.
Example:
H={famer’s hat, baseball
cap, hard hat}

24. 12. Rule method – writing elements
of set with the use of descriptor.
Example :
H={x/x covers and protects head.}
This is read as the set H
contains the element x such
that x covers and protects head.

25. 2. The symbol  or { } will
be used to refer to an empty
set.

26. 3. If F is a subset of A,
then we write
F  A
.

27. 4. The cardinality of a set
A is written as
n(A).

28. Do you have
questions?