Proving X^-1 is a Function: Demonstration

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Discussion Overview

The discussion revolves around the formal demonstration of whether the function g: P(A) > P(A) defined by g(X) = X^-1 (where X^-1 is interpreted as the inverse of X) is indeed a function. Participants are exploring the definitions and properties necessary to establish this claim, focusing on the concepts of domain, range, and the nature of the inverse operation in the context of set theory.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant asks how to formally prove that g is a function, indicating a need for clarity in definitions.
  • Another participant questions the meaning of "inverse of X," noting that a set does not have an inverse in the traditional sense.
  • A participant emphasizes the need to demonstrate that for every element in the domain, there is a corresponding solution, and that the solutions are unique.
  • Clarification is provided that P(A) refers to the power set of A, and X is defined as a set.
  • There is a proposal that the function being discussed is actually g(X) = X^c, where X^c denotes the complement of X.
  • One participant outlines two conditions to prove: that under the function X^c, any entry and exit belongs to P(A), and that there is uniqueness in the mapping of elements.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and implications of the terms used, particularly regarding the concept of an inverse in set theory. There is no consensus on how to proceed with the proof or the exact nature of the function being discussed.

Contextual Notes

There are unresolved questions about the definitions of A, P(A), and the specific nature of the inverse operation as applied to sets. The discussion reflects a lack of clarity on foundational concepts necessary for the proof.

FrostScYthe
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How do you prove this is a function?

g: P(A) > P(A)
g(X) = X^-1


X^-1 means inverse of X

anyway, does anyone know how to do a formal demonstration for this?
 
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You need to be a bit clearer. If this were NOT
 
You need to be a bit clearer. If this were NOT a "logic" question, I would assume you meant that g is a relation on the Power set of A. However, that would still leave open the question of what is meant by "inverse of X"- a set does not have an inverse.
 
Alright..

No, I do MEAN PROVE THAT IT IS A FUNCTION. somehow you first have to prove that for the domain there is a solution for every element.. and that there is Unity in the solutions for every element that x contains ;/

Now what I mean that X^c... it´s hard to put the friggin´ notation on that thing but it´s defined something like this

if xRy

then xR^cy means that yRx
that´s all :wink:

(x,y) belongs R
then (x,y) belongs R^-1 means (y,x) belongs R
 
You still haven't told us:

What A is.

What P(A) means.

What X is!
 
I though you were to know that ;\

but here we go anyway, I think I'm getting it solved from another source, so when I'll get it, I'll post it =d

P(A) - means Parts of set A

so when I say P(A) -> P(A) I simply mean that the function goes from a domain of P(A) to a range of P(A)

g(x) = X^c

That's the function that we're talking about. I believe I explained that one... X is a set by the way

What you have to prove?

1. That under the function X^c any entry and exit belongs to P(A)

2. That there's Unicity that is ...

for all x1 x2(g(x1) != g(x2) -> x1 != x2)
 

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