Whittaker model equation












2












$begingroup$


This is from Cogdell and Piateski-Shapiro's paper Derivative and L-functions for $GL_n$.



Let $lambda$ be a non-trivial $psi$-Whittaker functional. The Whittaker model is defined as$W_v(g)=lambda(pi(g)v), vin V_{pi},gin GL_n$. We know that $W_vin W(tau,psi)$ iff there is a compact open subgroup $Ysubset U_n$ such that $$int_Y W_v(py)psi^{-1}(y)dy=0, pin P_n.$$
I am confused why this can lead to: if writing $p=gu, gin GL_{n-1}, uin U_n$, we have
$$
int_YW_v(guy) psi^{-1}(y)dy=W_v(gu)int_Ypsi(gyg^{-1})psi^{-1}(y)dy.
$$

I understand it must be using the fact of $lambda$ being a Whittaker functional, but I am still unable to show $W_v(guy)=W_v(gu)psi(gyg^{-1}),$ frustrated..










share|cite|improve this question









$endgroup$












  • $begingroup$
    Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
    $endgroup$
    – Peter Humphries
    Jan 15 at 14:23
















2












$begingroup$


This is from Cogdell and Piateski-Shapiro's paper Derivative and L-functions for $GL_n$.



Let $lambda$ be a non-trivial $psi$-Whittaker functional. The Whittaker model is defined as$W_v(g)=lambda(pi(g)v), vin V_{pi},gin GL_n$. We know that $W_vin W(tau,psi)$ iff there is a compact open subgroup $Ysubset U_n$ such that $$int_Y W_v(py)psi^{-1}(y)dy=0, pin P_n.$$
I am confused why this can lead to: if writing $p=gu, gin GL_{n-1}, uin U_n$, we have
$$
int_YW_v(guy) psi^{-1}(y)dy=W_v(gu)int_Ypsi(gyg^{-1})psi^{-1}(y)dy.
$$

I understand it must be using the fact of $lambda$ being a Whittaker functional, but I am still unable to show $W_v(guy)=W_v(gu)psi(gyg^{-1}),$ frustrated..










share|cite|improve this question









$endgroup$












  • $begingroup$
    Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
    $endgroup$
    – Peter Humphries
    Jan 15 at 14:23














2












2








2





$begingroup$


This is from Cogdell and Piateski-Shapiro's paper Derivative and L-functions for $GL_n$.



Let $lambda$ be a non-trivial $psi$-Whittaker functional. The Whittaker model is defined as$W_v(g)=lambda(pi(g)v), vin V_{pi},gin GL_n$. We know that $W_vin W(tau,psi)$ iff there is a compact open subgroup $Ysubset U_n$ such that $$int_Y W_v(py)psi^{-1}(y)dy=0, pin P_n.$$
I am confused why this can lead to: if writing $p=gu, gin GL_{n-1}, uin U_n$, we have
$$
int_YW_v(guy) psi^{-1}(y)dy=W_v(gu)int_Ypsi(gyg^{-1})psi^{-1}(y)dy.
$$

I understand it must be using the fact of $lambda$ being a Whittaker functional, but I am still unable to show $W_v(guy)=W_v(gu)psi(gyg^{-1}),$ frustrated..










share|cite|improve this question









$endgroup$




This is from Cogdell and Piateski-Shapiro's paper Derivative and L-functions for $GL_n$.



Let $lambda$ be a non-trivial $psi$-Whittaker functional. The Whittaker model is defined as$W_v(g)=lambda(pi(g)v), vin V_{pi},gin GL_n$. We know that $W_vin W(tau,psi)$ iff there is a compact open subgroup $Ysubset U_n$ such that $$int_Y W_v(py)psi^{-1}(y)dy=0, pin P_n.$$
I am confused why this can lead to: if writing $p=gu, gin GL_{n-1}, uin U_n$, we have
$$
int_YW_v(guy) psi^{-1}(y)dy=W_v(gu)int_Ypsi(gyg^{-1})psi^{-1}(y)dy.
$$

I understand it must be using the fact of $lambda$ being a Whittaker functional, but I am still unable to show $W_v(guy)=W_v(gu)psi(gyg^{-1}),$ frustrated..







functional-analysis number-theory representation-theory automorphic-forms






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 9 at 4:38









AlahoiAlahoi

215




215












  • $begingroup$
    Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
    $endgroup$
    – Peter Humphries
    Jan 15 at 14:23


















  • $begingroup$
    Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
    $endgroup$
    – Peter Humphries
    Jan 15 at 14:23
















$begingroup$
Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
$endgroup$
– Peter Humphries
Jan 15 at 14:23




$begingroup$
Perhaps try emailing Cogdell? I had a look at that paper but was also unable to derive this equality.
$endgroup$
– Peter Humphries
Jan 15 at 14:23










1 Answer
1






active

oldest

votes


















0












$begingroup$

We just need to show $W_v(guy)=W_v(gu)psi(gyg^{-1})$.



In fact, since $guyu^{-1}g^{-1}in U_n$, and it is easy to verify $psi(guyu^{-1}g^{-1})=psi(gyg^{-1})$, hence
$$
W_v(guy)=W_v(guyu^{-1}g^{-1}gu)=psi(guyu^{-1}g^{-1})W_v(gu)=W_v(gu)psi(gyg^{-1}).
$$






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%2f3067073%2fwhittaker-model-equation%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












    $begingroup$

    We just need to show $W_v(guy)=W_v(gu)psi(gyg^{-1})$.



    In fact, since $guyu^{-1}g^{-1}in U_n$, and it is easy to verify $psi(guyu^{-1}g^{-1})=psi(gyg^{-1})$, hence
    $$
    W_v(guy)=W_v(guyu^{-1}g^{-1}gu)=psi(guyu^{-1}g^{-1})W_v(gu)=W_v(gu)psi(gyg^{-1}).
    $$






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      We just need to show $W_v(guy)=W_v(gu)psi(gyg^{-1})$.



      In fact, since $guyu^{-1}g^{-1}in U_n$, and it is easy to verify $psi(guyu^{-1}g^{-1})=psi(gyg^{-1})$, hence
      $$
      W_v(guy)=W_v(guyu^{-1}g^{-1}gu)=psi(guyu^{-1}g^{-1})W_v(gu)=W_v(gu)psi(gyg^{-1}).
      $$






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        We just need to show $W_v(guy)=W_v(gu)psi(gyg^{-1})$.



        In fact, since $guyu^{-1}g^{-1}in U_n$, and it is easy to verify $psi(guyu^{-1}g^{-1})=psi(gyg^{-1})$, hence
        $$
        W_v(guy)=W_v(guyu^{-1}g^{-1}gu)=psi(guyu^{-1}g^{-1})W_v(gu)=W_v(gu)psi(gyg^{-1}).
        $$






        share|cite|improve this answer









        $endgroup$



        We just need to show $W_v(guy)=W_v(gu)psi(gyg^{-1})$.



        In fact, since $guyu^{-1}g^{-1}in U_n$, and it is easy to verify $psi(guyu^{-1}g^{-1})=psi(gyg^{-1})$, hence
        $$
        W_v(guy)=W_v(guyu^{-1}g^{-1}gu)=psi(guyu^{-1}g^{-1})W_v(gu)=W_v(gu)psi(gyg^{-1}).
        $$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 28 at 17:06









        AlahoiAlahoi

        215




        215






























            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%2f3067073%2fwhittaker-model-equation%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

            Probability when a professor distributes a quiz and homework assignment to a class of n students.

            Aardman Animations

            Are they similar matrix