Doubt about a paragraph in the book “Algebraic Number Theory by Neukirch”.












0












$begingroup$


Please refer to the question in the given link.



The question already has an answer here



An element is integral iff its minimal polynomial has integral coefficients.



My question is ---



Here, $A$ is integrally closed in $K$. And $beta_i$'s $in bar{K}$. Don't we have to show that $beta_i$'s $in K$ to show they belong to $A$? Because $A$ is integrally closed in $K$ not in $bar{K}$.



Thank you.










share|cite|improve this question











$endgroup$

















    0












    $begingroup$


    Please refer to the question in the given link.



    The question already has an answer here



    An element is integral iff its minimal polynomial has integral coefficients.



    My question is ---



    Here, $A$ is integrally closed in $K$. And $beta_i$'s $in bar{K}$. Don't we have to show that $beta_i$'s $in K$ to show they belong to $A$? Because $A$ is integrally closed in $K$ not in $bar{K}$.



    Thank you.










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      Please refer to the question in the given link.



      The question already has an answer here



      An element is integral iff its minimal polynomial has integral coefficients.



      My question is ---



      Here, $A$ is integrally closed in $K$. And $beta_i$'s $in bar{K}$. Don't we have to show that $beta_i$'s $in K$ to show they belong to $A$? Because $A$ is integrally closed in $K$ not in $bar{K}$.



      Thank you.










      share|cite|improve this question











      $endgroup$




      Please refer to the question in the given link.



      The question already has an answer here



      An element is integral iff its minimal polynomial has integral coefficients.



      My question is ---



      Here, $A$ is integrally closed in $K$. And $beta_i$'s $in bar{K}$. Don't we have to show that $beta_i$'s $in K$ to show they belong to $A$? Because $A$ is integrally closed in $K$ not in $bar{K}$.



      Thank you.







      algebraic-number-theory






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 29 at 16:44







      Saikat

















      asked Jan 29 at 16:01









      SaikatSaikat

      366216




      366216






















          1 Answer
          1






          active

          oldest

          votes


















          0












          $begingroup$

          Here, $beta_i$'s belong to $bar{K}$ which are integral over $A$. So, coefficients of $p(x)$ are integral over $A$. But the coefficients of $p(x)$ belong to $K$. So, coefficients of $p(x)$ belong to $A$ as $A$ is integrally closed in $K$. Hence, $p(x)in A[x]$.






          share|cite|improve this answer









          $endgroup$














            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%2f3092339%2fdoubt-about-a-paragraph-in-the-book-algebraic-number-theory-by-neukirch%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












            $begingroup$

            Here, $beta_i$'s belong to $bar{K}$ which are integral over $A$. So, coefficients of $p(x)$ are integral over $A$. But the coefficients of $p(x)$ belong to $K$. So, coefficients of $p(x)$ belong to $A$ as $A$ is integrally closed in $K$. Hence, $p(x)in A[x]$.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              Here, $beta_i$'s belong to $bar{K}$ which are integral over $A$. So, coefficients of $p(x)$ are integral over $A$. But the coefficients of $p(x)$ belong to $K$. So, coefficients of $p(x)$ belong to $A$ as $A$ is integrally closed in $K$. Hence, $p(x)in A[x]$.






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                Here, $beta_i$'s belong to $bar{K}$ which are integral over $A$. So, coefficients of $p(x)$ are integral over $A$. But the coefficients of $p(x)$ belong to $K$. So, coefficients of $p(x)$ belong to $A$ as $A$ is integrally closed in $K$. Hence, $p(x)in A[x]$.






                share|cite|improve this answer









                $endgroup$



                Here, $beta_i$'s belong to $bar{K}$ which are integral over $A$. So, coefficients of $p(x)$ are integral over $A$. But the coefficients of $p(x)$ belong to $K$. So, coefficients of $p(x)$ belong to $A$ as $A$ is integrally closed in $K$. Hence, $p(x)in A[x]$.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 29 at 17:42









                SaikatSaikat

                366216




                366216






























                    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%2f3092339%2fdoubt-about-a-paragraph-in-the-book-algebraic-number-theory-by-neukirch%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

                    MongoDB - Not Authorized To Execute Command

                    in spring boot 2.1 many test slices are not allowed anymore due to multiple @BootstrapWith

                    How to fix TextFormField cause rebuild widget in Flutter