Characteristic of a field is not equal to zero











up vote
3
down vote

favorite












Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?










share|cite|improve this question


























    up vote
    3
    down vote

    favorite












    Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?










    share|cite|improve this question
























      up vote
      3
      down vote

      favorite









      up vote
      3
      down vote

      favorite











      Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?










      share|cite|improve this question













      Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?







      field-theory






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked 16 hours ago









      J.Bosser

      314210




      314210






















          2 Answers
          2






          active

          oldest

          votes

















          up vote
          4
          down vote



          accepted










          Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.






          share|cite|improve this answer




























            up vote
            3
            down vote













            Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.



            For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.






            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%2f3039431%2fcharacteristic-of-a-field-is-not-equal-to-zero%23new-answer', 'question_page');
              }
              );

              Post as a guest















              Required, but never shown

























              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes








              up vote
              4
              down vote



              accepted










              Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.






              share|cite|improve this answer

























                up vote
                4
                down vote



                accepted










                Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.






                share|cite|improve this answer























                  up vote
                  4
                  down vote



                  accepted







                  up vote
                  4
                  down vote



                  accepted






                  Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.






                  share|cite|improve this answer












                  Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered 16 hours ago









                  Matthew Towers

                  7,42922244




                  7,42922244






















                      up vote
                      3
                      down vote













                      Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.



                      For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.






                      share|cite|improve this answer



























                        up vote
                        3
                        down vote













                        Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.



                        For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.






                        share|cite|improve this answer

























                          up vote
                          3
                          down vote










                          up vote
                          3
                          down vote









                          Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.



                          For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.






                          share|cite|improve this answer














                          Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.



                          For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.







                          share|cite|improve this answer














                          share|cite|improve this answer



                          share|cite|improve this answer








                          edited 16 hours ago

























                          answered 16 hours ago









                          Wuestenfux

                          3,0351410




                          3,0351410






























                              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.





                              Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


                              Please pay close attention to the following guidance:


                              • 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.


                              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%2f3039431%2fcharacteristic-of-a-field-is-not-equal-to-zero%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

                              Plaza Victoria

                              In PowerPoint, is there a keyboard shortcut for bulleted / numbered list?

                              How to put 3 figures in Latex with 2 figures side by side and 1 below these side by side images but in...