Binary relation finding the transitive closure












1












$begingroup$


Let $A={a,b,c}$ and the relation given by the following matrix: $mathcal M_r=begin{pmatrix}1&0&1\0&1&0\1&1&0end{pmatrix}$



The task is to find the smallest transitive relation $E$ such that $rsubseteq E$. Which is equivalent of saying find the transitive closure of $r$.



so what I know is that: $t(r)=cup_{ngeq0}r^n, r^n=rcirc rcirc rcirc...circ r, n$ times.



so $mathcal M_{t(r)}=sum_{ninmathbb{N}}mathcal (M_r)^n$ and this gives me $$mathcal M_{t(r)}=begin{pmatrix}1&1&1\0&1&0\1&1&1end{pmatrix}$$



Is there something wrong in my approach?










share|cite|improve this question











$endgroup$












  • $begingroup$
    It's not clear how do you calculate $mathcal M_r^n$ and their sum?
    $endgroup$
    – Berci
    Jan 18 at 14:28












  • $begingroup$
    @Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
    $endgroup$
    – C. Cristi
    Jan 18 at 14:41












  • $begingroup$
    The result is correct. For this specific small example there's a shorter way to solve, though.
    $endgroup$
    – Berci
    Jan 18 at 14:45










  • $begingroup$
    @Berci Which way?
    $endgroup$
    – C. Cristi
    Jan 18 at 14:45
















1












$begingroup$


Let $A={a,b,c}$ and the relation given by the following matrix: $mathcal M_r=begin{pmatrix}1&0&1\0&1&0\1&1&0end{pmatrix}$



The task is to find the smallest transitive relation $E$ such that $rsubseteq E$. Which is equivalent of saying find the transitive closure of $r$.



so what I know is that: $t(r)=cup_{ngeq0}r^n, r^n=rcirc rcirc rcirc...circ r, n$ times.



so $mathcal M_{t(r)}=sum_{ninmathbb{N}}mathcal (M_r)^n$ and this gives me $$mathcal M_{t(r)}=begin{pmatrix}1&1&1\0&1&0\1&1&1end{pmatrix}$$



Is there something wrong in my approach?










share|cite|improve this question











$endgroup$












  • $begingroup$
    It's not clear how do you calculate $mathcal M_r^n$ and their sum?
    $endgroup$
    – Berci
    Jan 18 at 14:28












  • $begingroup$
    @Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
    $endgroup$
    – C. Cristi
    Jan 18 at 14:41












  • $begingroup$
    The result is correct. For this specific small example there's a shorter way to solve, though.
    $endgroup$
    – Berci
    Jan 18 at 14:45










  • $begingroup$
    @Berci Which way?
    $endgroup$
    – C. Cristi
    Jan 18 at 14:45














1












1








1





$begingroup$


Let $A={a,b,c}$ and the relation given by the following matrix: $mathcal M_r=begin{pmatrix}1&0&1\0&1&0\1&1&0end{pmatrix}$



The task is to find the smallest transitive relation $E$ such that $rsubseteq E$. Which is equivalent of saying find the transitive closure of $r$.



so what I know is that: $t(r)=cup_{ngeq0}r^n, r^n=rcirc rcirc rcirc...circ r, n$ times.



so $mathcal M_{t(r)}=sum_{ninmathbb{N}}mathcal (M_r)^n$ and this gives me $$mathcal M_{t(r)}=begin{pmatrix}1&1&1\0&1&0\1&1&1end{pmatrix}$$



Is there something wrong in my approach?










share|cite|improve this question











$endgroup$




Let $A={a,b,c}$ and the relation given by the following matrix: $mathcal M_r=begin{pmatrix}1&0&1\0&1&0\1&1&0end{pmatrix}$



The task is to find the smallest transitive relation $E$ such that $rsubseteq E$. Which is equivalent of saying find the transitive closure of $r$.



so what I know is that: $t(r)=cup_{ngeq0}r^n, r^n=rcirc rcirc rcirc...circ r, n$ times.



so $mathcal M_{t(r)}=sum_{ninmathbb{N}}mathcal (M_r)^n$ and this gives me $$mathcal M_{t(r)}=begin{pmatrix}1&1&1\0&1&0\1&1&1end{pmatrix}$$



Is there something wrong in my approach?







relations binary






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 18 at 19:21









Kevin Long

3,58121431




3,58121431










asked Jan 18 at 13:50









C. CristiC. Cristi

1,655318




1,655318












  • $begingroup$
    It's not clear how do you calculate $mathcal M_r^n$ and their sum?
    $endgroup$
    – Berci
    Jan 18 at 14:28












  • $begingroup$
    @Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
    $endgroup$
    – C. Cristi
    Jan 18 at 14:41












  • $begingroup$
    The result is correct. For this specific small example there's a shorter way to solve, though.
    $endgroup$
    – Berci
    Jan 18 at 14:45










  • $begingroup$
    @Berci Which way?
    $endgroup$
    – C. Cristi
    Jan 18 at 14:45


















  • $begingroup$
    It's not clear how do you calculate $mathcal M_r^n$ and their sum?
    $endgroup$
    – Berci
    Jan 18 at 14:28












  • $begingroup$
    @Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
    $endgroup$
    – C. Cristi
    Jan 18 at 14:41












  • $begingroup$
    The result is correct. For this specific small example there's a shorter way to solve, though.
    $endgroup$
    – Berci
    Jan 18 at 14:45










  • $begingroup$
    @Berci Which way?
    $endgroup$
    – C. Cristi
    Jan 18 at 14:45
















$begingroup$
It's not clear how do you calculate $mathcal M_r^n$ and their sum?
$endgroup$
– Berci
Jan 18 at 14:28






$begingroup$
It's not clear how do you calculate $mathcal M_r^n$ and their sum?
$endgroup$
– Berci
Jan 18 at 14:28














$begingroup$
@Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
$endgroup$
– C. Cristi
Jan 18 at 14:41






$begingroup$
@Berci Using logic operators, $+$ is denoted as OR and $.$ is denoted as AND. And $n$ is the cardinal of set $A$
$endgroup$
– C. Cristi
Jan 18 at 14:41














$begingroup$
The result is correct. For this specific small example there's a shorter way to solve, though.
$endgroup$
– Berci
Jan 18 at 14:45




$begingroup$
The result is correct. For this specific small example there's a shorter way to solve, though.
$endgroup$
– Berci
Jan 18 at 14:45












$begingroup$
@Berci Which way?
$endgroup$
– C. Cristi
Jan 18 at 14:45




$begingroup$
@Berci Which way?
$endgroup$
– C. Cristi
Jan 18 at 14:45










1 Answer
1






active

oldest

votes


















1












$begingroup$

Your solution is correct



If our graph is small like this, we can simply draw it (loops at $a$ and $b$ and arrows $ato c, bto c, cto a$), and then use that we have an arrow $xto y$ in the transitive closure iff there is a path $xleadsto y$ in the original graph.






share|cite|improve this answer









$endgroup$














    Your Answer








    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "69"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3078270%2fbinary-relation-finding-the-transitive-closure%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1












    $begingroup$

    Your solution is correct



    If our graph is small like this, we can simply draw it (loops at $a$ and $b$ and arrows $ato c, bto c, cto a$), and then use that we have an arrow $xto y$ in the transitive closure iff there is a path $xleadsto y$ in the original graph.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      Your solution is correct



      If our graph is small like this, we can simply draw it (loops at $a$ and $b$ and arrows $ato c, bto c, cto a$), and then use that we have an arrow $xto y$ in the transitive closure iff there is a path $xleadsto y$ in the original graph.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        Your solution is correct



        If our graph is small like this, we can simply draw it (loops at $a$ and $b$ and arrows $ato c, bto c, cto a$), and then use that we have an arrow $xto y$ in the transitive closure iff there is a path $xleadsto y$ in the original graph.






        share|cite|improve this answer









        $endgroup$



        Your solution is correct



        If our graph is small like this, we can simply draw it (loops at $a$ and $b$ and arrows $ato c, bto c, cto a$), and then use that we have an arrow $xto y$ in the transitive closure iff there is a path $xleadsto y$ in the original graph.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 18 at 18:37









        BerciBerci

        62k23776




        62k23776






























            draft saved

            draft discarded




















































            Thanks for contributing an answer to Mathematics Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3078270%2fbinary-relation-finding-the-transitive-closure%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            Human spaceflight

            Can not write log (Is /dev/pts mounted?) - openpty in Ubuntu-on-Windows?

            File:DeusFollowingSea.jpg