A binary hook-length formula? Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?Finite nilpotent orbits: GL(n,q)-conjugacy classes and a partial order on partitionsLinking formulas by Euler, Pólya, Nekrasov-Okounkovpartitions into odd parts vs hooks and symplectic contentshooks and contents: Part IHooks in a staircase partition: Part IA link between hooks, contents and parts of a partitionA link between hooks and contents: Part IIGenerating function for $3$-core partitionsGenerating function for 3 -core partitions: Part IIhook-length formula: “Fibonaccized” Part I

A binary hook-length formula?



Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)
Announcing the arrival of Valued Associate #679: Cesar Manara
Unicorn Meta Zoo #1: Why another podcast?Finite nilpotent orbits: GL(n,q)-conjugacy classes and a partial order on partitionsLinking formulas by Euler, Pólya, Nekrasov-Okounkovpartitions into odd parts vs hooks and symplectic contentshooks and contents: Part IHooks in a staircase partition: Part IA link between hooks, contents and parts of a partitionA link between hooks and contents: Part IIGenerating function for $3$-core partitionsGenerating function for 3 -core partitions: Part IIhook-length formula: “Fibonaccized” Part I










5












$begingroup$


This is purely exploratory and inspired by curiosity.



Setup: For an integer $k>0$, let $k=sum_jgeq0k_j2^j$ be its binary expansion and denote the sum of its digits by $eta(k):=sum_jk_j$. Further, introduce a binary factorial
$$[n]!_b:=eta(1)eta(2)cdotseta(n).$$
Given an integer partition $lambda$, let $Y_lambda$ be the corresponding Young diagram. If $square$ a cell in $Y_lambda$, construct its hook-length $h_square$ in the usual manner but replace it by $eta(h_square)$.



For example, take $lambda=(3,2,1)$ then its multiset of hooks is $h_square:squarein Y_lambda=5,3,1,3,1,1$ which shall be replaced by $eta(h_square):squarein Y_lambda=2,2,1,2,1,1$.



Naturally, we define the (new) product of hook-lengths and denote (with an abuse of notation)
$$H_lambda=prod_squareinlambdaeta(h_square).$$
If $lambdavdash n$, it is easy to verify that $frac[n]!_bH_lambda$ is an integer.




QUESTION. What do these integer count?
$$sum_lambdavdash nfrac[n]!_bH_lambda.$$




The first few values are: $1, 2, 3, 7, 10, 23, 52, 82, 117, 258, dots$ but not listed on OEIS.










share|cite|improve this question











$endgroup$
















    5












    $begingroup$


    This is purely exploratory and inspired by curiosity.



    Setup: For an integer $k>0$, let $k=sum_jgeq0k_j2^j$ be its binary expansion and denote the sum of its digits by $eta(k):=sum_jk_j$. Further, introduce a binary factorial
    $$[n]!_b:=eta(1)eta(2)cdotseta(n).$$
    Given an integer partition $lambda$, let $Y_lambda$ be the corresponding Young diagram. If $square$ a cell in $Y_lambda$, construct its hook-length $h_square$ in the usual manner but replace it by $eta(h_square)$.



    For example, take $lambda=(3,2,1)$ then its multiset of hooks is $h_square:squarein Y_lambda=5,3,1,3,1,1$ which shall be replaced by $eta(h_square):squarein Y_lambda=2,2,1,2,1,1$.



    Naturally, we define the (new) product of hook-lengths and denote (with an abuse of notation)
    $$H_lambda=prod_squareinlambdaeta(h_square).$$
    If $lambdavdash n$, it is easy to verify that $frac[n]!_bH_lambda$ is an integer.




    QUESTION. What do these integer count?
    $$sum_lambdavdash nfrac[n]!_bH_lambda.$$




    The first few values are: $1, 2, 3, 7, 10, 23, 52, 82, 117, 258, dots$ but not listed on OEIS.










    share|cite|improve this question











    $endgroup$














      5












      5








      5


      2



      $begingroup$


      This is purely exploratory and inspired by curiosity.



      Setup: For an integer $k>0$, let $k=sum_jgeq0k_j2^j$ be its binary expansion and denote the sum of its digits by $eta(k):=sum_jk_j$. Further, introduce a binary factorial
      $$[n]!_b:=eta(1)eta(2)cdotseta(n).$$
      Given an integer partition $lambda$, let $Y_lambda$ be the corresponding Young diagram. If $square$ a cell in $Y_lambda$, construct its hook-length $h_square$ in the usual manner but replace it by $eta(h_square)$.



      For example, take $lambda=(3,2,1)$ then its multiset of hooks is $h_square:squarein Y_lambda=5,3,1,3,1,1$ which shall be replaced by $eta(h_square):squarein Y_lambda=2,2,1,2,1,1$.



      Naturally, we define the (new) product of hook-lengths and denote (with an abuse of notation)
      $$H_lambda=prod_squareinlambdaeta(h_square).$$
      If $lambdavdash n$, it is easy to verify that $frac[n]!_bH_lambda$ is an integer.




      QUESTION. What do these integer count?
      $$sum_lambdavdash nfrac[n]!_bH_lambda.$$




      The first few values are: $1, 2, 3, 7, 10, 23, 52, 82, 117, 258, dots$ but not listed on OEIS.










      share|cite|improve this question











      $endgroup$




      This is purely exploratory and inspired by curiosity.



      Setup: For an integer $k>0$, let $k=sum_jgeq0k_j2^j$ be its binary expansion and denote the sum of its digits by $eta(k):=sum_jk_j$. Further, introduce a binary factorial
      $$[n]!_b:=eta(1)eta(2)cdotseta(n).$$
      Given an integer partition $lambda$, let $Y_lambda$ be the corresponding Young diagram. If $square$ a cell in $Y_lambda$, construct its hook-length $h_square$ in the usual manner but replace it by $eta(h_square)$.



      For example, take $lambda=(3,2,1)$ then its multiset of hooks is $h_square:squarein Y_lambda=5,3,1,3,1,1$ which shall be replaced by $eta(h_square):squarein Y_lambda=2,2,1,2,1,1$.



      Naturally, we define the (new) product of hook-lengths and denote (with an abuse of notation)
      $$H_lambda=prod_squareinlambdaeta(h_square).$$
      If $lambdavdash n$, it is easy to verify that $frac[n]!_bH_lambda$ is an integer.




      QUESTION. What do these integer count?
      $$sum_lambdavdash nfrac[n]!_bH_lambda.$$




      The first few values are: $1, 2, 3, 7, 10, 23, 52, 82, 117, 258, dots$ but not listed on OEIS.







      nt.number-theory co.combinatorics rt.representation-theory partitions






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited 2 days ago







      T. Amdeberhan

















      asked 2 days ago









      T. AmdeberhanT. Amdeberhan

      18.5k230132




      18.5k230132




















          1 Answer
          1






          active

          oldest

          votes


















          10












          $begingroup$

          I am afraid they are not always integers. Take large $p$ and $n=2^2p-1$. Then $[n]!_b$ is divisible by $p^N$ for $N=2pchoose p+1$. And $[2n+1]!_b$ by $p^K$ for $K=2p+1choose p+2p+1<2N$. Then for $2times N$ diagram we get $p$ in the denominator.






          share|cite|improve this answer









          $endgroup$













            Your Answer








            StackExchange.ready(function()
            var channelOptions =
            tags: "".split(" "),
            id: "504"
            ;
            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%2fmathoverflow.net%2fquestions%2f328254%2fa-binary-hook-length-formula%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









            10












            $begingroup$

            I am afraid they are not always integers. Take large $p$ and $n=2^2p-1$. Then $[n]!_b$ is divisible by $p^N$ for $N=2pchoose p+1$. And $[2n+1]!_b$ by $p^K$ for $K=2p+1choose p+2p+1<2N$. Then for $2times N$ diagram we get $p$ in the denominator.






            share|cite|improve this answer









            $endgroup$

















              10












              $begingroup$

              I am afraid they are not always integers. Take large $p$ and $n=2^2p-1$. Then $[n]!_b$ is divisible by $p^N$ for $N=2pchoose p+1$. And $[2n+1]!_b$ by $p^K$ for $K=2p+1choose p+2p+1<2N$. Then for $2times N$ diagram we get $p$ in the denominator.






              share|cite|improve this answer









              $endgroup$















                10












                10








                10





                $begingroup$

                I am afraid they are not always integers. Take large $p$ and $n=2^2p-1$. Then $[n]!_b$ is divisible by $p^N$ for $N=2pchoose p+1$. And $[2n+1]!_b$ by $p^K$ for $K=2p+1choose p+2p+1<2N$. Then for $2times N$ diagram we get $p$ in the denominator.






                share|cite|improve this answer









                $endgroup$



                I am afraid they are not always integers. Take large $p$ and $n=2^2p-1$. Then $[n]!_b$ is divisible by $p^N$ for $N=2pchoose p+1$. And $[2n+1]!_b$ by $p^K$ for $K=2p+1choose p+2p+1<2N$. Then for $2times N$ diagram we get $p$ in the denominator.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 2 days ago









                Fedor PetrovFedor Petrov

                52.4k6122241




                52.4k6122241



























                    draft saved

                    draft discarded
















































                    Thanks for contributing an answer to MathOverflow!


                    • 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%2fmathoverflow.net%2fquestions%2f328254%2fa-binary-hook-length-formula%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

                    Get product attribute by attribute group code in magento 2get product attribute by product attribute group in magento 2Magento 2 Log Bundle Product Data in List Page?How to get all product attribute of a attribute group of Default attribute set?Magento 2.1 Create a filter in the product grid by new attributeMagento 2 : Get Product Attribute values By GroupMagento 2 How to get all existing values for one attributeMagento 2 get custom attribute of a single product inside a pluginMagento 2.3 How to get all the Multi Source Inventory (MSI) locations collection in custom module?Magento2: how to develop rest API to get new productsGet product attribute by attribute group code ( [attribute_group_code] ) in magento 2

                    Category:9 (number) SubcategoriesMedia in category "9 (number)"Navigation menuUpload mediaGND ID: 4485639-8Library of Congress authority ID: sh85091979ReasonatorScholiaStatistics

                    Magento 2.3: How do i solve this, Not registered handle, on custom form?How can i rewrite TierPrice Block in Magento2magento 2 captcha not rendering if I override layout xmlmain.CRITICAL: Plugin class doesn't existMagento 2 : Problem while adding custom button order view page?Magento 2.2.5: Overriding Admin Controller sales/orderMagento 2.2.5: Add, Update and Delete existing products Custom OptionsMagento 2.3 : File Upload issue in UI Component FormMagento2 Not registered handleHow to configured Form Builder Js in my custom magento 2.3.0 module?Magento 2.3. How to create image upload field in an admin form