List all the functions from the three-element set

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SUMMARY

The discussion centers on the enumeration of functions from a three-element set {1, 2, 3} to a two-element set {a, b}. The correct number of functions is established as 8, derived from the formula 2^3, indicating that each element in the domain can map to either of the two elements in the codomain. The confusion arises from a claim in a textbook that states there are 24 functions, which is incorrect. The participants clarify that the calculation of 8 functions is definitive and based on combinatorial principles.

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sampahmel
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Dear all,

List all the functions from the three-element set {1,2,3} to the set {a,b}.

The answer I have is 6 functions. However, the answer given at the back of the book has 24 functions:

Note: In the following functions, I will use (sub 1) denoting subscript 1.



f (sub 1) (1)=a , f (sub 1) (2)=a , f (sub 1) (3)=a
f (sub 2) (1)=a , f (sub 2) (2)=a , f (sub 2) (3)=b
f (sub 3) (1)=a , f (sub 3) (1)=b , f (sub 1) (1)=a
f (sub 4) (1)=a , f (sub 4) (1)=b , f (sub 4) (1)=b
f (sub 5) (1)=b , f (sub 5) (1)=a , f (sub 5) (1)=a
f (sub 6) (1)=b , f (sub 6) (1)=a , f (sub 6) (1)=b
f (sub 7) (1)=b , f (sub 7) (1)=b , f (sub 4) (1)=a
f (sub 8) (1)=b , f (sub 8) (1)=b , f (sub 8) (1)=b
 
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I think I did not make myself clear in the above thread.

I would like to know why are there 8 functions?
 


There are 8 functions. 8=2^3. If the book says there are 24, it's quite wrong.
 

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