How are inverse images used to prove set inclusions?

In summary, the inverse image of a set is the set of all elements in the domain that map to the given set through a function. It is closely related to the concept of function and is used to find the original input values for a given output value. The notation used for inverse image is f<sup>-1</sup>(S), where f is the function and S is the set in question. It is different from the image of a set, as the image is the set of all output values produced by a function for a given input set. The concept of inverse image has various real-world applications, such as data encryption, image processing, and machine learning, where it helps in finding the original input data from processed or encrypted output
  • #1
drmarchjune
1
0
I am studying the very first chapter of analysis, but can't quite get through this problem:

Prove f −1(f(A)) ⊇ A
Prove f(f −1(B)) ⊆ B
 
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  • #2
How did you begin the problem?
For [itex] A \subseteq f^{-1}( f(A)) [/itex], consider two cases.
case 1:[itex] A = \emptyset [/itex]
case 2: [itex] A \neq \emptyset [/itex]
 
  • #3
in general , to prove that [tex]A\subseteq B[/tex] , we prove

[tex]\forall x[x\in A\Rightarrow x\in B][/tex]


and to prove this ,you let x be arbitrary. since we have an implication inside the square bracket, we assume antecedent , and set out to prove consequent . So assume
[tex]x\in A[/tex]
 

Related to How are inverse images used to prove set inclusions?

1. What is the inverse image of a set?

The inverse image of a set is the set of all elements in the domain that map to the given set through a function. It is also known as the preimage of the set.

2. How is the inverse image related to the concept of function?

The inverse image is closely related to the concept of function. It is used to find the input values that produce a given output value. In other words, it helps us to determine the original input for a particular output in a function.

3. What is the notation used for inverse image?

The notation used for inverse image is f-1(S), where f is the function and S is the set in question. This notation is read as "the inverse image of S under f".

4. How is the inverse image different from the image of a set?

The inverse image and image of a set are two different concepts. The image of a set is the set of all output values produced by a function for a given input set. On the other hand, the inverse image is the set of all input values that produce a given output set.

5. How is the concept of inverse image used in real-world applications?

The concept of inverse image is used in various real-world applications, such as data encryption, image processing, and machine learning. It helps in finding the original input data from the processed or encrypted output data, which is crucial in many fields like security and data analysis.

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