Recurrence relation for the polygamma function of negative order?

Multi tool use
Multi tool use

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











up vote
0
down vote

favorite
1












I know the recurrence relation for the Polygamma function is



$$psi^(m)(x+1)=psi^(m)(x)+frac(-1)^mm!x^m+1$$



Does such a recurrence formula exist for negative integer $m$?



I am using the integral definition



$$psi^(-n)(x)=frac1(x-2)!int_0^x (x-t)^n-2ln(Gamma(t))dt$$ for $n$ a positive integer, which I assume is equal to the $(n-1)$th integral of $lnGamma(x)$.







share|cite|improve this question


















  • 1




    Well, what definition of "negapolygamma" are you using?
    – J. M. is not a mathematician
    Aug 17 '17 at 22:59










  • Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
    – Simply Beautiful Art
    Aug 14 at 1:57















up vote
0
down vote

favorite
1












I know the recurrence relation for the Polygamma function is



$$psi^(m)(x+1)=psi^(m)(x)+frac(-1)^mm!x^m+1$$



Does such a recurrence formula exist for negative integer $m$?



I am using the integral definition



$$psi^(-n)(x)=frac1(x-2)!int_0^x (x-t)^n-2ln(Gamma(t))dt$$ for $n$ a positive integer, which I assume is equal to the $(n-1)$th integral of $lnGamma(x)$.







share|cite|improve this question


















  • 1




    Well, what definition of "negapolygamma" are you using?
    – J. M. is not a mathematician
    Aug 17 '17 at 22:59










  • Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
    – Simply Beautiful Art
    Aug 14 at 1:57













up vote
0
down vote

favorite
1









up vote
0
down vote

favorite
1






1





I know the recurrence relation for the Polygamma function is



$$psi^(m)(x+1)=psi^(m)(x)+frac(-1)^mm!x^m+1$$



Does such a recurrence formula exist for negative integer $m$?



I am using the integral definition



$$psi^(-n)(x)=frac1(x-2)!int_0^x (x-t)^n-2ln(Gamma(t))dt$$ for $n$ a positive integer, which I assume is equal to the $(n-1)$th integral of $lnGamma(x)$.







share|cite|improve this question














I know the recurrence relation for the Polygamma function is



$$psi^(m)(x+1)=psi^(m)(x)+frac(-1)^mm!x^m+1$$



Does such a recurrence formula exist for negative integer $m$?



I am using the integral definition



$$psi^(-n)(x)=frac1(x-2)!int_0^x (x-t)^n-2ln(Gamma(t))dt$$ for $n$ a positive integer, which I assume is equal to the $(n-1)$th integral of $lnGamma(x)$.









share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Aug 18 '17 at 21:30

























asked Aug 17 '17 at 22:40









tyobrien

1,098412




1,098412







  • 1




    Well, what definition of "negapolygamma" are you using?
    – J. M. is not a mathematician
    Aug 17 '17 at 22:59










  • Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
    – Simply Beautiful Art
    Aug 14 at 1:57













  • 1




    Well, what definition of "negapolygamma" are you using?
    – J. M. is not a mathematician
    Aug 17 '17 at 22:59










  • Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
    – Simply Beautiful Art
    Aug 14 at 1:57








1




1




Well, what definition of "negapolygamma" are you using?
– J. M. is not a mathematician
Aug 17 '17 at 22:59




Well, what definition of "negapolygamma" are you using?
– J. M. is not a mathematician
Aug 17 '17 at 22:59












Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
– Simply Beautiful Art
Aug 14 at 1:57





Note: my answer has been updated to provide a more explicit recursive relation of the polygamma function on negative orders, using the provided definition.
– Simply Beautiful Art
Aug 14 at 1:57











1 Answer
1






active

oldest

votes

















up vote
3
down vote



accepted










Using your definition, we hence have



beginalignpsi^(-n)(x+1)&=psi^(-n)(x)+frac1(n-2)!int_0^x(x-t)^n-2ln(t)~dt+sum_k=0^n-2fracpsi^(k-n)(1)k!x^k\&=psi^(-n)(x)+fracx^n-1[ln(x)-H_n-1](n-1)!+sum_k=0^n-2fracpsi^(k-n)(1)k!x^kendalign



where $H_n=sum_k=^nfrac1k$ is the harmonic number.






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%2f2397454%2frecurrence-relation-for-the-polygamma-function-of-negative-order%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










    Using your definition, we hence have



    beginalignpsi^(-n)(x+1)&=psi^(-n)(x)+frac1(n-2)!int_0^x(x-t)^n-2ln(t)~dt+sum_k=0^n-2fracpsi^(k-n)(1)k!x^k\&=psi^(-n)(x)+fracx^n-1[ln(x)-H_n-1](n-1)!+sum_k=0^n-2fracpsi^(k-n)(1)k!x^kendalign



    where $H_n=sum_k=^nfrac1k$ is the harmonic number.






    share|cite|improve this answer


























      up vote
      3
      down vote



      accepted










      Using your definition, we hence have



      beginalignpsi^(-n)(x+1)&=psi^(-n)(x)+frac1(n-2)!int_0^x(x-t)^n-2ln(t)~dt+sum_k=0^n-2fracpsi^(k-n)(1)k!x^k\&=psi^(-n)(x)+fracx^n-1[ln(x)-H_n-1](n-1)!+sum_k=0^n-2fracpsi^(k-n)(1)k!x^kendalign



      where $H_n=sum_k=^nfrac1k$ is the harmonic number.






      share|cite|improve this answer
























        up vote
        3
        down vote



        accepted







        up vote
        3
        down vote



        accepted






        Using your definition, we hence have



        beginalignpsi^(-n)(x+1)&=psi^(-n)(x)+frac1(n-2)!int_0^x(x-t)^n-2ln(t)~dt+sum_k=0^n-2fracpsi^(k-n)(1)k!x^k\&=psi^(-n)(x)+fracx^n-1[ln(x)-H_n-1](n-1)!+sum_k=0^n-2fracpsi^(k-n)(1)k!x^kendalign



        where $H_n=sum_k=^nfrac1k$ is the harmonic number.






        share|cite|improve this answer














        Using your definition, we hence have



        beginalignpsi^(-n)(x+1)&=psi^(-n)(x)+frac1(n-2)!int_0^x(x-t)^n-2ln(t)~dt+sum_k=0^n-2fracpsi^(k-n)(1)k!x^k\&=psi^(-n)(x)+fracx^n-1[ln(x)-H_n-1](n-1)!+sum_k=0^n-2fracpsi^(k-n)(1)k!x^kendalign



        where $H_n=sum_k=^nfrac1k$ is the harmonic number.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Aug 14 at 1:55

























        answered Aug 17 '17 at 22:54









        Simply Beautiful Art

        49.4k572172




        49.4k572172






















             

            draft saved


            draft discarded


























             


            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2397454%2frecurrence-relation-for-the-polygamma-function-of-negative-order%23new-answer', 'question_page');

            );

            Post as a guest













































































            13 sWNPl6xNM,xJNwaQd3S0N,aPZ5 i pUHF,G9yfVH0C OPgUp
            BDwCvp9,cV4AkhdI7Q6T4yahSYIo KQE 8t0vP 5,4 C

            這個網誌中的熱門文章

            How to combine Bézier curves to a surface?

            Propositional logic and tautologies

            Distribution of Stopped Wiener Process with Stochastic Volatility