Inverse mapping of a singleton set

In summary, the inverse image of phi-inverse (5) of the singleton set {5} is either x=0, y=5 or x=5, y=0. For the product operation n(x,y)=xy, the inverse image of n-inverse (4) is either x=1, y=4 or x=4, y=1. It is not necessary to prove these solutions.
  • #1
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Homework Statement


For X= NxN, Y=N, define the mapping phi: X-->Y as phi(x,y)=x+y. Find the inverse image of phi-inverse (5) of the singleton set {5}. If n: X-->Y is the product operation n(x,y)=xy, find n-inverse (4).


The Attempt at a Solution


I'm not even really sure what the question is asking. If the set is a singleton set, does that mean it sets 5 to itself? So the inverse image would be 5...?

As for the product operation, I don't know how to approach it.
 
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  • #2
The inverse image of {5} is the set of all things that map to 5 under phi. In the first case all (x,y) in NxN such that x+y=5 and in the second case x*y=4. N is the natural numbers, right?
 
  • #3
N is the natural numbers.

So for x+y=5, the inverse image is either x=0,y=5, or x=5,y=0?

And the inverse image for xy=4 is either x=1,y=4, or x=4,y=1?

Do I have to show a proof for it though?
 
  • #4
How about x=1,y=4. Doesn't that work in the first case? And is 0 a natural number? I don't think you have all the solutions for the second case either. I'd just start by listing the possibilities. It doesn't seem to me like it's necessary to 'prove' it.
 

1. What is inverse mapping of a singleton set?

Inverse mapping of a singleton set is a mathematical concept that involves finding the input value or values that correspond to a specific output value in a function. It is essentially the reverse of a regular mapping, where the output value is known and the input value is unknown.

2. How is inverse mapping of a singleton set different from regular mapping?

In regular mapping, the input value is known and the output value is calculated using a function. Inverse mapping, on the other hand, involves finding the input value(s) that will result in a specific output value.

3. What is the purpose of inverse mapping of a singleton set?

The purpose of inverse mapping of a singleton set is to determine the original input value or values that led to a specific output value in a function. This can be useful in various mathematical and scientific applications, such as solving equations and analyzing data.

4. What are some common methods used for inverse mapping of a singleton set?

Some common methods used for inverse mapping of a singleton set include algebraic manipulation, graphing, and using inverse functions. Each method may be more suitable depending on the specific function and the available information.

5. Can inverse mapping of a singleton set be applied to any function?

Inverse mapping of a singleton set can be applied to many functions, but not all. It depends on the nature of the function and whether or not it is one-to-one, meaning that each input value corresponds to a unique output value. Functions that are not one-to-one may not have an inverse mapping.

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