What is a Weil-Deligne representation?












4












$begingroup$


Can anyone explain (or give reference) Weil-Deligne representations, and how they are linked with Galois representations of p-adic field (on l-adic vector spaces or else) ?










share|cite|improve this question









$endgroup$

















    4












    $begingroup$


    Can anyone explain (or give reference) Weil-Deligne representations, and how they are linked with Galois representations of p-adic field (on l-adic vector spaces or else) ?










    share|cite|improve this question









    $endgroup$















      4












      4








      4


      4



      $begingroup$


      Can anyone explain (or give reference) Weil-Deligne representations, and how they are linked with Galois representations of p-adic field (on l-adic vector spaces or else) ?










      share|cite|improve this question









      $endgroup$




      Can anyone explain (or give reference) Weil-Deligne representations, and how they are linked with Galois representations of p-adic field (on l-adic vector spaces or else) ?







      reference-request representation-theory galois-theory






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Sep 1 '11 at 21:48









      user10676user10676

      6,29021737




      6,29021737






















          1 Answer
          1






          active

          oldest

          votes


















          6












          $begingroup$

          The canonical reference is Tate's "Number Theoretic Background" in the Corvallis volume. He discusses the Weil-Deligne group in Section 4. Here is a brief description:



          Fix a local field $K$ with perfect residue field of characteristic $pneqell$, and let $W_K$ be the Weil group of $K$ (this is $phi^{-1}(mathbb{Z})$ where $phi:G_Krightarrowhat{mathbb{Z}}$ is the unramified quotient). A Weil-Deligne representation is a pair



          $(V,N)$



          where $V$ is a char. $0$ representation of $W_K$ on a discrete vector space and $N:Vrightarrow V(-1)$ is a morphism of representations. One important fact is that the category of $ell$-adic representations of $G_K$ embeds fully faithfully into the category of Weil-Deligne representations.



          Anyway, to get the full story, you should probably read Tate's article.



          EDIT: Another nice reference is Chapter 1 of (the current draft of) a book by Fontaine and Ouyang.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
            $endgroup$
            – Matt E
            Sep 2 '11 at 1:25










          • $begingroup$
            Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
            $endgroup$
            – Kevin Ventullo
            Sep 2 '11 at 2:44











          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',
          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%2f61278%2fwhat-is-a-weil-deligne-representation%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









          6












          $begingroup$

          The canonical reference is Tate's "Number Theoretic Background" in the Corvallis volume. He discusses the Weil-Deligne group in Section 4. Here is a brief description:



          Fix a local field $K$ with perfect residue field of characteristic $pneqell$, and let $W_K$ be the Weil group of $K$ (this is $phi^{-1}(mathbb{Z})$ where $phi:G_Krightarrowhat{mathbb{Z}}$ is the unramified quotient). A Weil-Deligne representation is a pair



          $(V,N)$



          where $V$ is a char. $0$ representation of $W_K$ on a discrete vector space and $N:Vrightarrow V(-1)$ is a morphism of representations. One important fact is that the category of $ell$-adic representations of $G_K$ embeds fully faithfully into the category of Weil-Deligne representations.



          Anyway, to get the full story, you should probably read Tate's article.



          EDIT: Another nice reference is Chapter 1 of (the current draft of) a book by Fontaine and Ouyang.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
            $endgroup$
            – Matt E
            Sep 2 '11 at 1:25










          • $begingroup$
            Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
            $endgroup$
            – Kevin Ventullo
            Sep 2 '11 at 2:44
















          6












          $begingroup$

          The canonical reference is Tate's "Number Theoretic Background" in the Corvallis volume. He discusses the Weil-Deligne group in Section 4. Here is a brief description:



          Fix a local field $K$ with perfect residue field of characteristic $pneqell$, and let $W_K$ be the Weil group of $K$ (this is $phi^{-1}(mathbb{Z})$ where $phi:G_Krightarrowhat{mathbb{Z}}$ is the unramified quotient). A Weil-Deligne representation is a pair



          $(V,N)$



          where $V$ is a char. $0$ representation of $W_K$ on a discrete vector space and $N:Vrightarrow V(-1)$ is a morphism of representations. One important fact is that the category of $ell$-adic representations of $G_K$ embeds fully faithfully into the category of Weil-Deligne representations.



          Anyway, to get the full story, you should probably read Tate's article.



          EDIT: Another nice reference is Chapter 1 of (the current draft of) a book by Fontaine and Ouyang.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
            $endgroup$
            – Matt E
            Sep 2 '11 at 1:25










          • $begingroup$
            Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
            $endgroup$
            – Kevin Ventullo
            Sep 2 '11 at 2:44














          6












          6








          6





          $begingroup$

          The canonical reference is Tate's "Number Theoretic Background" in the Corvallis volume. He discusses the Weil-Deligne group in Section 4. Here is a brief description:



          Fix a local field $K$ with perfect residue field of characteristic $pneqell$, and let $W_K$ be the Weil group of $K$ (this is $phi^{-1}(mathbb{Z})$ where $phi:G_Krightarrowhat{mathbb{Z}}$ is the unramified quotient). A Weil-Deligne representation is a pair



          $(V,N)$



          where $V$ is a char. $0$ representation of $W_K$ on a discrete vector space and $N:Vrightarrow V(-1)$ is a morphism of representations. One important fact is that the category of $ell$-adic representations of $G_K$ embeds fully faithfully into the category of Weil-Deligne representations.



          Anyway, to get the full story, you should probably read Tate's article.



          EDIT: Another nice reference is Chapter 1 of (the current draft of) a book by Fontaine and Ouyang.






          share|cite|improve this answer











          $endgroup$



          The canonical reference is Tate's "Number Theoretic Background" in the Corvallis volume. He discusses the Weil-Deligne group in Section 4. Here is a brief description:



          Fix a local field $K$ with perfect residue field of characteristic $pneqell$, and let $W_K$ be the Weil group of $K$ (this is $phi^{-1}(mathbb{Z})$ where $phi:G_Krightarrowhat{mathbb{Z}}$ is the unramified quotient). A Weil-Deligne representation is a pair



          $(V,N)$



          where $V$ is a char. $0$ representation of $W_K$ on a discrete vector space and $N:Vrightarrow V(-1)$ is a morphism of representations. One important fact is that the category of $ell$-adic representations of $G_K$ embeds fully faithfully into the category of Weil-Deligne representations.



          Anyway, to get the full story, you should probably read Tate's article.



          EDIT: Another nice reference is Chapter 1 of (the current draft of) a book by Fontaine and Ouyang.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 30 '18 at 3:34

























          answered Sep 1 '11 at 22:50









          Kevin VentulloKevin Ventullo

          2,13911422




          2,13911422












          • $begingroup$
            Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
            $endgroup$
            – Matt E
            Sep 2 '11 at 1:25










          • $begingroup$
            Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
            $endgroup$
            – Kevin Ventullo
            Sep 2 '11 at 2:44


















          • $begingroup$
            Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
            $endgroup$
            – Matt E
            Sep 2 '11 at 1:25










          • $begingroup$
            Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
            $endgroup$
            – Kevin Ventullo
            Sep 2 '11 at 2:44
















          $begingroup$
          Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
          $endgroup$
          – Matt E
          Sep 2 '11 at 1:25




          $begingroup$
          Dear Kevin, Note that if $ell neq p$, then every $ell$-adic representation of $G_K$ is "potentially semi-stable", and so corresponds to a Weil--Deligne representation. Regards,
          $endgroup$
          – Matt E
          Sep 2 '11 at 1:25












          $begingroup$
          Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
          $endgroup$
          – Kevin Ventullo
          Sep 2 '11 at 2:44




          $begingroup$
          Dear Matt, Thank you for your comment. I started out trying to write about an arbitrary complete DVF but changed my mind and ended up with some garbage. I have edited to reflect your remark.
          $endgroup$
          – Kevin Ventullo
          Sep 2 '11 at 2:44


















          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%2f61278%2fwhat-is-a-weil-deligne-representation%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

          Human spaceflight

          Can not write log (Is /dev/pts mounted?) - openpty in Ubuntu-on-Windows?

          張江高科駅