Proving Existence of Surjective Function F from P(N)\N to P(N)

In summary, the conversation is discussing the definition of a function $F$ and its properties, specifically whether or not there exists a surjective function from the power set of natural numbers excluding the natural numbers themselves to the power set of natural numbers. The definition of $F$ given is incomplete and the additional conditions do not uniquely define $S$ and $R$. The question about the existence of such a function can be answered affirmatively due to the cardinality of the sets involved.
  • #1
Ella1
2
0
I'd really like some help in answering the next question...anything that might help will save my life:

F is defined this way: F:A→B where A,B⊂P(N) and P(N) is the power set of the naturals.
Let S,R∈A such that S is a proper subset of R if and only if F(S) is a proper subset of F(R)

My question is to prove whether or not there is an F from P(N)∖N to P(N) which is also a surjective function?
 
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  • #2
Ella said:
F is defined this way: F:A→B where A,B⊂P(N) and P(N) is the power set of the naturals.
This is not a complete definition of $F$. This just fixes (to some unknown $A$ and $B$) the domain and codomain of $F$ and not the rule that establishes which sets are mapped to which sets.

Ella said:
Let S,R∈A such that S is a proper subset of R if and only if F(S) is a proper subset of F(R)
This does not define $S$ and $R$ uniquely, so I am not sure what the role of this phrase is. Perhaps it is supposed to be a restriction on $F$ and this property is supposed to hold for all $S$ and $R$.

Ella said:
My question is to prove whether or not there is an F from P(N)∖N to P(N) which is also a surjective function?
Since the question is about the existence of $F$, the previous definition of $F$ is apparently irrelevant. Without any restrictions, yes, there exists a bijection between $P(\mathbb{N})\setminus\mathbb{N}$ and $P(\mathbb{N})$ because both sets has cardinality continuum.
 

1. What is set theory?

Set theory is a branch of mathematics that deals with the study of sets, which are collections of objects. It provides a foundation for all of mathematics and is used in various fields such as computer science, statistics, and physics.

2. What is a problem in set theory?

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3. What is the Continuum Hypothesis?

The Continuum Hypothesis is a famous problem in set theory that was first proposed by Georg Cantor in the late 19th century. It states that there is no set whose size is strictly between the size of the integers and the size of the real numbers. This problem has been studied by many mathematicians and has yet to be solved.

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Problems in set theory are typically solved using logical reasoning, axioms, and theorems. The first step is to clearly understand the problem and then use known concepts and techniques to come up with a solution or proof. Collaboration and discussions with other mathematicians can also help in solving these problems.

5. Why is set theory important?

Set theory is important because it provides a rigorous and logical foundation for all of mathematics. It allows us to define and manipulate abstract concepts, which are crucial in many fields of study. Set theory also has practical applications in computer science, statistics, and physics, making it an essential tool for scientists and researchers.

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