Results 1 to 2 of 2

Math Help - Relations of sets

  1. #1
    Member
    Joined
    Sep 2008
    Posts
    239

    Relations of sets

    This is my question :-

    For each of the following relations on the set {2, 3, 4, 5, 6, 7, 8} say whether the relation is reflexive, whether it is symetric, whether it is transitive and whether it is an equivalence relation.

    a P b iff a and b have no common factor greater than 1.
    a Q b iff the smaller of a and b is greater than 4.
    a R b iff a + b is a multiple of 2.

    Justify your answers and draw the diagraph for each relation. For those relations that are equivalence relations, describe the equivalence classes.




    Right I apologize now for the fact I have not done any working out simply because I don't have a clue how to even start it! I'm trying to learn it now as I go along but don't have much time so thought I would look for help on here as well as the text book (which isn't making sense right now) so I have two points of view on the question. I'm stuck on two more questions which I will post on sperate threads too. Thanks for any help it's much appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Drexel28's Avatar
    Joined
    Nov 2009
    From
    Berkeley, California
    Posts
    4,563
    Thanks
    21
    Quote Originally Posted by djmccabie View Post
    This is my question :-

    For each of the following relations on the set {2, 3, 4, 5, 6, 7, 8} say whether the relation is reflexive, whether it is symetric, whether it is transitive and whether it is an equivalence relation.

    a P b iff a and b have no common factor greater than 1.
    a Q b iff the smaller of a and b is greater than 4.
    a R b iff a + b is a multiple of 2.

    Justify your answers and draw the diagraph for each relation. For those relations that are equivalence relations, describe the equivalence classes.




    Right I apologize now for the fact I have not done any working out simply because I don't have a clue how to even start it! I'm trying to learn it now as I go along but don't have much time so thought I would look for help on here as well as the text book (which isn't making sense right now) so I have two points of view on the question. I'm stuck on two more questions which I will post on sperate threads too. Thanks for any help it's much appreciated.
    I'll help with the first one.

    So a\sim b\Longleftrightarrow (a,b)=1.

    This is not reflexive since 2\not\sim 2 because (2,2)=2
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Sets and Relations
    Posted in the Discrete Math Forum
    Replies: 10
    Last Post: May 24th 2010, 12:28 PM
  2. more sets and relations
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: November 5th 2008, 07:37 PM
  3. sets and relations #2
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: November 5th 2008, 07:31 PM
  4. Sets and relations
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 4th 2008, 07:38 AM
  5. sets and relations
    Posted in the Discrete Math Forum
    Replies: 5
    Last Post: June 28th 2008, 10:43 PM

Search Tags


/mathhelpforum @mathhelpforum