Proving Powerset P and Intersection N: A Midterm Study Guide

  • Thread starter Klion
  • Start date
  • Tags
    Proof
In summary: Thanks for the help!In summary, the question asks you to prove that if x is in the set P(A∩B) then x is also in the set P(A)∩P(B). To do this, you first need to define what a subset is and then use the equivalence principle to show that each element of x is also an element of both sets.
  • #1
Klion
14
0
P for powerset, n for intersection

show that P(AnB)=P(A) n P(B)

Studying for a midterm, seen this question in our textbook and on an old midterm. No idea how to do it. Anyone know?
 
Last edited:
Physics news on Phys.org
  • #2
It's pretty basic, just apply definitions, and you should be ok.
Just prove that if x is in P(A ∩ B) then x is also in P(A) ∩ P(B), and
that if x is in P(A) ∩ P(B) then x is in P(A ∩ B).

It should just be applying definitions.
 
  • #3
I know the idea behind doing a proof heh, I think my textbook is somewhat lacking though. What definitions shoudl I be attempting to make use of. Only info I've found on powersets in textbook is what the powerset actually is (the set containing all the subsets). Cant think of any helpful way to apply that to a general case though.
 
  • #4
Ok:

x is in P(A ∩ B) is equivalent to saying that
x is a subset of A ∩ B
so each element χ of x is in A ∩ B
so each element χ of x is in A and in B
so x is a subset of A and x is a subset of B
so x is in P(A) and x is in P(B)

you should have no problem filling in the holes, and going in the other direction from there.
 
  • #5
Shouldn't that be x is an element of...
 
  • #6
Shouldn't that be x is an element of...

No, x is a subset of A∩B is correct.

x is an element of P(A∩B) which is the collection of all subsets of A∩B.
 
  • #7
I see, set theory is quite new to me, it was taken off our curriclum at school and isn't much used in undergraduate physics (well not in the first year anyway).
 

Q: What is Powerset proof?

Powerset proof is a mathematical proof technique used to prove statements about sets. It involves breaking down a set into its power set, which is a set of all possible subsets, and then using logical arguments to prove the statement for each subset.

Q: What makes Powerset proof different from other proof techniques?

Powerset proof is different from other proof techniques because it specifically uses the concept of power sets and subsets to prove statements about sets. This can be particularly useful when dealing with complex or infinite sets.

Q: When should Powerset proof be used?

Powerset proof should be used when the statement being proved involves a set or sets, and the proof can be simplified by breaking down the set into its power set. It can also be useful when dealing with infinite sets, as it allows for a more efficient and concise proof.

Q: What are the advantages of using Powerset proof?

One advantage of Powerset proof is that it can simplify complex proofs involving sets by breaking them down into smaller, more manageable subsets. It also allows for a more systematic and organized approach to proving statements about sets.

Q: Are there any limitations to Powerset proof?

While Powerset proof can be a useful technique, it may not be applicable to all types of statements or problems. It also requires a good understanding of sets and logical arguments, so it may not be suitable for all levels of mathematical knowledge.

Similar threads

  • Set Theory, Logic, Probability, Statistics
Replies
2
Views
1K
  • Set Theory, Logic, Probability, Statistics
Replies
16
Views
2K
  • Set Theory, Logic, Probability, Statistics
Replies
19
Views
2K
  • Set Theory, Logic, Probability, Statistics
Replies
4
Views
866
  • Set Theory, Logic, Probability, Statistics
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
24
Views
783
  • Set Theory, Logic, Probability, Statistics
Replies
1
Views
1K
  • Set Theory, Logic, Probability, Statistics
Replies
1
Views
2K
  • Set Theory, Logic, Probability, Statistics
Replies
3
Views
1K
Back
Top