How many incongruent primitive roots does 13 have?












1












$begingroup$


How many incongruent primitive roots does 13 have?:



So far I know that phi(phi(13)) = phi(12) = 4, so there would be 4 primitive roots. And a RRS mod 13 is {1,2,3,...,12}. But I'm not sure where to go from here to find the incongruent primitive roots. Any help would be appreciated!










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    $13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
    $endgroup$
    – Daniel Fischer
    Feb 4 '16 at 0:52










  • $begingroup$
    The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
    $endgroup$
    – André Nicolas
    Feb 4 '16 at 1:43
















1












$begingroup$


How many incongruent primitive roots does 13 have?:



So far I know that phi(phi(13)) = phi(12) = 4, so there would be 4 primitive roots. And a RRS mod 13 is {1,2,3,...,12}. But I'm not sure where to go from here to find the incongruent primitive roots. Any help would be appreciated!










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    $13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
    $endgroup$
    – Daniel Fischer
    Feb 4 '16 at 0:52










  • $begingroup$
    The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
    $endgroup$
    – André Nicolas
    Feb 4 '16 at 1:43














1












1








1


1



$begingroup$


How many incongruent primitive roots does 13 have?:



So far I know that phi(phi(13)) = phi(12) = 4, so there would be 4 primitive roots. And a RRS mod 13 is {1,2,3,...,12}. But I'm not sure where to go from here to find the incongruent primitive roots. Any help would be appreciated!










share|cite|improve this question









$endgroup$




How many incongruent primitive roots does 13 have?:



So far I know that phi(phi(13)) = phi(12) = 4, so there would be 4 primitive roots. And a RRS mod 13 is {1,2,3,...,12}. But I'm not sure where to go from here to find the incongruent primitive roots. Any help would be appreciated!







number-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Feb 4 '16 at 0:49









whatarethosewhatarethose

285




285








  • 2




    $begingroup$
    $13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
    $endgroup$
    – Daniel Fischer
    Feb 4 '16 at 0:52










  • $begingroup$
    The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
    $endgroup$
    – André Nicolas
    Feb 4 '16 at 1:43














  • 2




    $begingroup$
    $13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
    $endgroup$
    – Daniel Fischer
    Feb 4 '16 at 0:52










  • $begingroup$
    The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
    $endgroup$
    – André Nicolas
    Feb 4 '16 at 1:43








2




2




$begingroup$
$13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
$endgroup$
– Daniel Fischer
Feb 4 '16 at 0:52




$begingroup$
$13$ is small, you could brute-force it. But if you have found one primitive root, do you know how to get the others from it?
$endgroup$
– Daniel Fischer
Feb 4 '16 at 0:52












$begingroup$
The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
$endgroup$
– André Nicolas
Feb 4 '16 at 1:43




$begingroup$
The only candidates are the quadratic non-residues. That cuts down on the work. There are further shortcuts, which are not worth using here.
$endgroup$
– André Nicolas
Feb 4 '16 at 1:43










1 Answer
1






active

oldest

votes


















0












$begingroup$

The four incongruent primitive roots of $13$ are $g^k$ for $g$ a primitive root and $k$ coprime with $12$, that is, $k=1,5,7,11$. They can also be given by $pm g, pm g^5$ because $g^6=-1$.






share|cite|improve this answer











$endgroup$













    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    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%2f1639588%2fhow-many-incongruent-primitive-roots-does-13-have%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









    0












    $begingroup$

    The four incongruent primitive roots of $13$ are $g^k$ for $g$ a primitive root and $k$ coprime with $12$, that is, $k=1,5,7,11$. They can also be given by $pm g, pm g^5$ because $g^6=-1$.






    share|cite|improve this answer











    $endgroup$


















      0












      $begingroup$

      The four incongruent primitive roots of $13$ are $g^k$ for $g$ a primitive root and $k$ coprime with $12$, that is, $k=1,5,7,11$. They can also be given by $pm g, pm g^5$ because $g^6=-1$.






      share|cite|improve this answer











      $endgroup$
















        0












        0








        0





        $begingroup$

        The four incongruent primitive roots of $13$ are $g^k$ for $g$ a primitive root and $k$ coprime with $12$, that is, $k=1,5,7,11$. They can also be given by $pm g, pm g^5$ because $g^6=-1$.






        share|cite|improve this answer











        $endgroup$



        The four incongruent primitive roots of $13$ are $g^k$ for $g$ a primitive root and $k$ coprime with $12$, that is, $k=1,5,7,11$. They can also be given by $pm g, pm g^5$ because $g^6=-1$.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Dec 26 '18 at 10:23

























        answered Feb 4 '16 at 1:12









        lhflhf

        166k10171400




        166k10171400






























            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%2f1639588%2fhow-many-incongruent-primitive-roots-does-13-have%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

            Mario Kart Wii

            What does “Dominus providebit” mean?

            Antonio Litta Visconti Arese