How to find $(mathbb Z/12times mathbb Z/12)/$?

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
2
down vote

favorite












Consider $G=mathbb Z/12times mathbb Z/12$ and its subgroup $H$ generated by $(a^4,a^6)$, where $a$ is a generator of $mathbb Z/12$. How do I find $G/H$ as a product of cyclic groups of prime power orders?



I know how to identify similar quotients in the case $mathbb Ztimes mathbb Z$ via reducing a matrix to the Smith normal form (see this answer for instance), but I don't know whether such technique carries over to this case.







share|cite|improve this question















  • 3




    You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
    – ancientmathematician
    Jul 19 at 6:46














up vote
2
down vote

favorite












Consider $G=mathbb Z/12times mathbb Z/12$ and its subgroup $H$ generated by $(a^4,a^6)$, where $a$ is a generator of $mathbb Z/12$. How do I find $G/H$ as a product of cyclic groups of prime power orders?



I know how to identify similar quotients in the case $mathbb Ztimes mathbb Z$ via reducing a matrix to the Smith normal form (see this answer for instance), but I don't know whether such technique carries over to this case.







share|cite|improve this question















  • 3




    You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
    – ancientmathematician
    Jul 19 at 6:46












up vote
2
down vote

favorite









up vote
2
down vote

favorite











Consider $G=mathbb Z/12times mathbb Z/12$ and its subgroup $H$ generated by $(a^4,a^6)$, where $a$ is a generator of $mathbb Z/12$. How do I find $G/H$ as a product of cyclic groups of prime power orders?



I know how to identify similar quotients in the case $mathbb Ztimes mathbb Z$ via reducing a matrix to the Smith normal form (see this answer for instance), but I don't know whether such technique carries over to this case.







share|cite|improve this question











Consider $G=mathbb Z/12times mathbb Z/12$ and its subgroup $H$ generated by $(a^4,a^6)$, where $a$ is a generator of $mathbb Z/12$. How do I find $G/H$ as a product of cyclic groups of prime power orders?



I know how to identify similar quotients in the case $mathbb Ztimes mathbb Z$ via reducing a matrix to the Smith normal form (see this answer for instance), but I don't know whether such technique carries over to this case.









share|cite|improve this question










share|cite|improve this question




share|cite|improve this question









asked Jul 19 at 5:59









user437309

556212




556212







  • 3




    You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
    – ancientmathematician
    Jul 19 at 6:46












  • 3




    You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
    – ancientmathematician
    Jul 19 at 6:46







3




3




You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
– ancientmathematician
Jul 19 at 6:46




You can use the Smith algorithm once you recognise you can step back and then consider $mathbbZtimesmathbbZ$ factored by $langle (12,0), (0,12), (4,6)rangle$.
– ancientmathematician
Jul 19 at 6:46










1 Answer
1






active

oldest

votes

















up vote
3
down vote



accepted










Note that $H=langle(a^4,0),(0,a^6)rangle$ (this is not trivial, so it has to be proven, but it's quite easy), and by the third isomorphism theorem, you can divide out by one element at a time. So we get $$Bbb Z/12timesBbb Z/12/langle(a^4,0),(0,a^6)rangle\cong big(Bbb Z/12timesBbb Z12/langle(a^4,0)ranglebig)/langle(0,a^6)rangle\congBbb Z/4timesBbb Z/6$$






share|cite|improve this answer























    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',
    convertImagesToLinks: true,
    noModals: false,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    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%2f2856306%2fhow-to-find-mathbb-z-12-times-mathbb-z-12-a4-a6%23new-answer', 'question_page');

    );

    Post as a guest






























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    3
    down vote



    accepted










    Note that $H=langle(a^4,0),(0,a^6)rangle$ (this is not trivial, so it has to be proven, but it's quite easy), and by the third isomorphism theorem, you can divide out by one element at a time. So we get $$Bbb Z/12timesBbb Z/12/langle(a^4,0),(0,a^6)rangle\cong big(Bbb Z/12timesBbb Z12/langle(a^4,0)ranglebig)/langle(0,a^6)rangle\congBbb Z/4timesBbb Z/6$$






    share|cite|improve this answer



























      up vote
      3
      down vote



      accepted










      Note that $H=langle(a^4,0),(0,a^6)rangle$ (this is not trivial, so it has to be proven, but it's quite easy), and by the third isomorphism theorem, you can divide out by one element at a time. So we get $$Bbb Z/12timesBbb Z/12/langle(a^4,0),(0,a^6)rangle\cong big(Bbb Z/12timesBbb Z12/langle(a^4,0)ranglebig)/langle(0,a^6)rangle\congBbb Z/4timesBbb Z/6$$






      share|cite|improve this answer

























        up vote
        3
        down vote



        accepted







        up vote
        3
        down vote



        accepted






        Note that $H=langle(a^4,0),(0,a^6)rangle$ (this is not trivial, so it has to be proven, but it's quite easy), and by the third isomorphism theorem, you can divide out by one element at a time. So we get $$Bbb Z/12timesBbb Z/12/langle(a^4,0),(0,a^6)rangle\cong big(Bbb Z/12timesBbb Z12/langle(a^4,0)ranglebig)/langle(0,a^6)rangle\congBbb Z/4timesBbb Z/6$$






        share|cite|improve this answer















        Note that $H=langle(a^4,0),(0,a^6)rangle$ (this is not trivial, so it has to be proven, but it's quite easy), and by the third isomorphism theorem, you can divide out by one element at a time. So we get $$Bbb Z/12timesBbb Z/12/langle(a^4,0),(0,a^6)rangle\cong big(Bbb Z/12timesBbb Z12/langle(a^4,0)ranglebig)/langle(0,a^6)rangle\congBbb Z/4timesBbb Z/6$$







        share|cite|improve this answer















        share|cite|improve this answer



        share|cite|improve this answer








        edited Jul 19 at 6:24


























        answered Jul 19 at 6:09









        Arthur

        98.8k793175




        98.8k793175






















             

            draft saved


            draft discarded


























             


            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2856306%2fhow-to-find-mathbb-z-12-times-mathbb-z-12-a4-a6%23new-answer', 'question_page');

            );

            Post as a guest













































































            Comments

            Popular posts from this blog

            What is the equation of a 3D cone with generalised tilt?

            Color the edges and diagonals of a regular polygon

            Relationship between determinant of matrix and determinant of adjoint?