Set Theory
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Transcript of Set Theory
Copyright © 2014, 2010, 2007 Pearson Education, Inc.Copyright © 2014, 2010, 2007 Pearson Education, Inc.
Section 2.1, Slide 1
Set Theory2 Set Theory
Using Mathematics to Classify Objects
Copyright © 2014, 2010, 2007 Pearson Education, Inc.Copyright © 2014, 2010, 2007 Pearson Education, Inc.
Section 2.1, Slide 2
The Language of Sets2.1
• Specify sets using both listing and set-builder notation
• Understand when sets are well-defined
• Use the element symbol property
(continued on next slide)
Copyright © 2014, 2010, 2007 Pearson Education, Inc.Copyright © 2014, 2010, 2007 Pearson Education, Inc.
Section 2.1, Slide 3
The Language of Sets2.1
• Find the cardinal number of sets
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 4
Representing Sets
• Set – collection of objects
• Element – a member of a set
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 5
Representing Sets
• Set-builder notation:
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 6
Representing Sets
• Set – collection of objects
• Element – a member of a set
• Set-builder notation:
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 7
Representing Sets
• A set is well-defined if we are able to tell whether any particular object is an element of the set.
• Example: Which sets are well-defined?
(a)
(b) : is a winner of an Academy AwardA x x
: is tallT x x
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 8
Representing Sets
• Do and {} mean the same thing?
is the empty set – a set with no members– {} is a set with a member object, namely, the empty
set
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 9
Representing Sets
• Example: Consider female consumers living in the U.S. The universal set is
: is a female cosumer living in the U.S.U x x
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 10
The Element Symbol
• Example:
means "is an element of" means "is an element of"not
2,3,4,53
6 2,3,4,5
Copyright © 2014, 2010, 2007 Pearson Education, Inc. Section 2.1, Slide 11
Cardinal Number
• Example: State the cardinal number of the set.
1,2,3 , 1,4,5 , 3X
3
(the set contains 3 objects, each of which is also a set)
n X
X