26. Some Special Sets
The Null Set or Empty Set. This is a set with
no elements, often symbolized by
or { }
The Universal Set. This is the set of all elements
currently under consideration, and is often
symbolized by
U
27. Universal Sets
The universal set is the set of all things pertinent to a
given discussion and is designated by the symbol U
Example:
U = {all students at AMAU}
Some Subsets:
A = {all Computer Technology students}
B = {freshmen students}
C = {sophomore students}
30. Universal Sets
4,7,8,21
4,5,8,13
4,5,7,14
4,5,7,8,13,14,21
The sets B, V, and F are
contained in the universal
set, then these sets are also
called subsets of the
Universal set.
B ⊂ U (A is the subset of U)
V ⊂ U (B is the subset of U)
F ⊂ U (C is the subset of U)
33. Power Set
In set theory, the power set (or
power set) of a Set A is defined as the set of
all subsets of the Set A including the Set
itself and the null or empty set. It is
denoted by P(A). Basically, this set is the
combination of all subsets including null
set, of a given set.
34. Power Set
In set theory, the
power set (or power set) of
a Set A is defined as the set
of all subsets of the Set A
including the Set itself and
the null or empty set. It is
denoted by P(A). Basically,
this set is the combination
of all subsets including null
set, of a given set.
A = { a, b, c }
P(A) = { { } , { a }, { b },
{ c }, { a, b }, { b, c },
{ c, a }, { a, b, c } }
2𝑛
23
=8
35. Find the Subsets
What are all the subsets of C={3, 4, 5}
P(C)={} or Ø, {3}, {4}, {5} {3,4}, {3,5}, {4,5} {3,4,5}
50. More Practice:
U = {1, 2, 3, 4, 5} is the universal set and
A = {2, 3}. What is A′?
U = {a, b} is the universal set and
T = {a}. What is T′?
U = {+, -, x, ÷, =} is the universal set and
A = {÷, =}. What is A′?