Lower bound for sum of Hecke eigenvalues











up vote
2
down vote

favorite












Let $lambda$ be weakly multiplicative, $lambda(n)geq0$, $p$ prime and $S(x)=sum_{nleq x}lambda(n)log(frac{x}{n})$ for real $x$.



How can I show $S(x)gg left(sum_{pleq sqrt{x/3}}lambda(p)right)^2-left(sum_{pleq sqrt{x/3}}1right)$?



Here is the background:
The question is coming from IKS, section 3. $lambda(n)$ are the eigenvalues of a newform $f$ of level $N$. All above sums are chosen such that $(n,N)=1$ or $pnotmid N$, thus giving multiplicativity.



In Xu, section 3.1 something similar happens. Here the hints $lambda(p)^2=lambda(p^2)+1$ (which leads to $lambda(p)geq1$ and $|lambda(n)|leqsigma_0(n)$ (divisor function) are given.










share|cite|improve this question




























    up vote
    2
    down vote

    favorite












    Let $lambda$ be weakly multiplicative, $lambda(n)geq0$, $p$ prime and $S(x)=sum_{nleq x}lambda(n)log(frac{x}{n})$ for real $x$.



    How can I show $S(x)gg left(sum_{pleq sqrt{x/3}}lambda(p)right)^2-left(sum_{pleq sqrt{x/3}}1right)$?



    Here is the background:
    The question is coming from IKS, section 3. $lambda(n)$ are the eigenvalues of a newform $f$ of level $N$. All above sums are chosen such that $(n,N)=1$ or $pnotmid N$, thus giving multiplicativity.



    In Xu, section 3.1 something similar happens. Here the hints $lambda(p)^2=lambda(p^2)+1$ (which leads to $lambda(p)geq1$ and $|lambda(n)|leqsigma_0(n)$ (divisor function) are given.










    share|cite|improve this question


























      up vote
      2
      down vote

      favorite









      up vote
      2
      down vote

      favorite











      Let $lambda$ be weakly multiplicative, $lambda(n)geq0$, $p$ prime and $S(x)=sum_{nleq x}lambda(n)log(frac{x}{n})$ for real $x$.



      How can I show $S(x)gg left(sum_{pleq sqrt{x/3}}lambda(p)right)^2-left(sum_{pleq sqrt{x/3}}1right)$?



      Here is the background:
      The question is coming from IKS, section 3. $lambda(n)$ are the eigenvalues of a newform $f$ of level $N$. All above sums are chosen such that $(n,N)=1$ or $pnotmid N$, thus giving multiplicativity.



      In Xu, section 3.1 something similar happens. Here the hints $lambda(p)^2=lambda(p^2)+1$ (which leads to $lambda(p)geq1$ and $|lambda(n)|leqsigma_0(n)$ (divisor function) are given.










      share|cite|improve this question















      Let $lambda$ be weakly multiplicative, $lambda(n)geq0$, $p$ prime and $S(x)=sum_{nleq x}lambda(n)log(frac{x}{n})$ for real $x$.



      How can I show $S(x)gg left(sum_{pleq sqrt{x/3}}lambda(p)right)^2-left(sum_{pleq sqrt{x/3}}1right)$?



      Here is the background:
      The question is coming from IKS, section 3. $lambda(n)$ are the eigenvalues of a newform $f$ of level $N$. All above sums are chosen such that $(n,N)=1$ or $pnotmid N$, thus giving multiplicativity.



      In Xu, section 3.1 something similar happens. Here the hints $lambda(p)^2=lambda(p^2)+1$ (which leads to $lambda(p)geq1$ and $|lambda(n)|leqsigma_0(n)$ (divisor function) are given.







      number-theory eigenvalues-eigenvectors estimation modular-forms upper-lower-bounds






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Nov 20 at 14:14

























      asked Nov 12 at 13:17









      Nodt Greenish

      30513




      30513






















          1 Answer
          1






          active

          oldest

          votes

















          up vote
          0
          down vote



          accepted










          I found a way which should do the trick. I think the division by 3 is just a technical detail and 2 would be already sufficient to pull $log(frac{x}{x/2})$ out of the sum. You can take $S(x)=sum_{nleq x}lambda(n)log(x/n)geq sum_{pqleq x/2}lambda(pq)$. Furthermore we use the formula $lambda(p)^2=lambda(p^2)+1$, which is (1.2) in IKS., to estimate the case $p=q$. That's where the subtracted sum of 1's comes from.






          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: 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%2f2995298%2flower-bound-for-sum-of-hecke-eigenvalues%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








            up vote
            0
            down vote



            accepted










            I found a way which should do the trick. I think the division by 3 is just a technical detail and 2 would be already sufficient to pull $log(frac{x}{x/2})$ out of the sum. You can take $S(x)=sum_{nleq x}lambda(n)log(x/n)geq sum_{pqleq x/2}lambda(pq)$. Furthermore we use the formula $lambda(p)^2=lambda(p^2)+1$, which is (1.2) in IKS., to estimate the case $p=q$. That's where the subtracted sum of 1's comes from.






            share|cite|improve this answer



























              up vote
              0
              down vote



              accepted










              I found a way which should do the trick. I think the division by 3 is just a technical detail and 2 would be already sufficient to pull $log(frac{x}{x/2})$ out of the sum. You can take $S(x)=sum_{nleq x}lambda(n)log(x/n)geq sum_{pqleq x/2}lambda(pq)$. Furthermore we use the formula $lambda(p)^2=lambda(p^2)+1$, which is (1.2) in IKS., to estimate the case $p=q$. That's where the subtracted sum of 1's comes from.






              share|cite|improve this answer

























                up vote
                0
                down vote



                accepted







                up vote
                0
                down vote



                accepted






                I found a way which should do the trick. I think the division by 3 is just a technical detail and 2 would be already sufficient to pull $log(frac{x}{x/2})$ out of the sum. You can take $S(x)=sum_{nleq x}lambda(n)log(x/n)geq sum_{pqleq x/2}lambda(pq)$. Furthermore we use the formula $lambda(p)^2=lambda(p^2)+1$, which is (1.2) in IKS., to estimate the case $p=q$. That's where the subtracted sum of 1's comes from.






                share|cite|improve this answer














                I found a way which should do the trick. I think the division by 3 is just a technical detail and 2 would be already sufficient to pull $log(frac{x}{x/2})$ out of the sum. You can take $S(x)=sum_{nleq x}lambda(n)log(x/n)geq sum_{pqleq x/2}lambda(pq)$. Furthermore we use the formula $lambda(p)^2=lambda(p^2)+1$, which is (1.2) in IKS., to estimate the case $p=q$. That's where the subtracted sum of 1's comes from.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Nov 22 at 8:40

























                answered Nov 20 at 14:12









                Nodt Greenish

                30513




                30513






























                     

                    draft saved


                    draft discarded



















































                     


                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2995298%2flower-bound-for-sum-of-hecke-eigenvalues%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

                    Ellipse (mathématiques)

                    Quarter-circle Tiles

                    Mont Emei