Unformatted text preview: A → B . For any X ⊆ A , de±ne the image of X under f to be f [ X ] def = { f ( a ) : a ∈ X } The set f [ A ] of all images of f is called the image set of f . We explore some examples. Since functions are special binary relations, we can use the representations given in section 3 to describe relations. When the domain and codomain are ±nite, a useful representation is the diagram representation. 1. Let A = { 1 , 2 , 3 } and B = { a,b, c } . Let f ⊆ A × B be de±ned by f = { (1 , a ) , (2 , b ) , (3 , a ) } . Then f is a function, as is clear to see from the diagram: A B 1 2 3 a b c The image set of f is { a,b } . The image of { 1 , 3 } under f is { a } . 31...
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This note was uploaded on 01/02/2010 for the course MATH Math2009 taught by Professor Koskesh during the Spring '09 term at SUNY Empire State.
 Spring '09
 Koskesh
 Math

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