Results 1 to 4 of 4

Math Help - Define a relation

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    62

    Question Define a relation

    Let A={a,b,c} and P(A) be the power set of A ( the family of subsets of A)

    Define the relation  \approx on P(A) defined by  B,C \epsilon P(A) ,  B \approx C if and only if B and C contain the same number of elements.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Aug 2009
    From
    Israel
    Posts
    976
    What is the question?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Sep 2009
    Posts
    62
    he wants us to find the the relation of this power set?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Feb 2010
    Posts
    466
    Thanks
    4
    Maybe you mean he wants you to explicitly LIST the members of the relation.

    Let A = {a b c}

    PA = {0 {a} {b} {c} {a b} {a c} {b c} {a b c}}

    Let R = {<x y> | x in PA, y in PA, and x and y are equinumerous}

    So R =

    {<0 0>
    <{a} {a}>
    <{b} {b}>
    <{c} {c}>
    <{a} {b}>
    <{b} {a}>
    <{a} {c}>
    <{c} {a}>
    <{b} {c}>
    <{c} {b}>
    <{a b} {a b}>
    <{a c} {a c}>
    <{b c} {b c}>
    <{a b} {a c}>
    <{a c} {a b}>
    <{a b} {b c}>
    <{b c} {a b}>
    <{a c} {b c}>
    <{b c} {a c}>
    <{a b c} {a b c}>}

    That was boring. I have no idea why I bothered doing it.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 11
    Last Post: December 5th 2011, 08:30 PM
  2. Replies: 1
    Last Post: April 7th 2011, 12:46 AM
  3. Replies: 2
    Last Post: November 13th 2010, 08:27 AM
  4. Replies: 1
    Last Post: March 13th 2010, 01:13 PM
  5. define a relation...
    Posted in the Discrete Math Forum
    Replies: 12
    Last Post: December 3rd 2008, 12:21 PM

Search Tags


/mathhelpforum @mathhelpforum