Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

vishal_kothari

Suppose that for every (including the empty set and the whole set) subset X of a finite set S there is a subset X∗ of S and suppose that if X is a subset of Y then X∗ is a subset of Y∗ . Show that there is a subset A of S satisfying A∗ = A

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. KingGeorge
    Best Response
    You've already chosen the best response.
    Medals 1

    Hold on, I'm getting confused here.

    • 2 years ago
  2. KingGeorge
    Best Response
    You've already chosen the best response.
    Medals 1

    It says that "for every subset \(X \subseteq S\) there is a subset \(X* \subseteq S\). Thus, if \(A \subseteq S\) then \(A* \subseteq S\). We also know by the second hypothesis that \(A* \subseteq S*\). But this is basically just restating the hypotheses.

    • 2 years ago
  3. vishal_kothari
    Best Response
    You've already chosen the best response.
    Medals 1

    i m confused too....

    • 2 years ago
  4. KingGeorge
    Best Response
    You've already chosen the best response.
    Medals 1

    Could we just let \(A = \emptyset \) ? Then \(A* = \emptyset\) and since the empty set is contained in every set, the claim is true.

    • 2 years ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.