If either $f_n longrightarrow f $ almost everywhere OR $f_n longrightarrow f$












0














[1] Are all simple functions Lebesgue Integrable? Prove or disprove.



[2] If either $f_n longrightarrow f $ almost everywhere OR $f_n longrightarrow f$ in measure then show that f is finite valued (ie real valued) almost everywhere.



MY ATTEMPT



[1] I'm not sure if all simple functions are Lebesgue integrable or not but this is my example of a simple function which is not Lebesgue integrable



Let $(mathbb{R},B_mathbb{R},mu_L)$ be a Lebesgue measure space and



$phi:[0,infty] longrightarrow mathbb{R}$ is a simple function defined as



$$
phi(x)=
begin{cases}
-1, if x in bigcup_{x in mathbb{Z^+}} [2k+1,2k+2],\
1, if x in bigcup_{x in mathbb{Z^+}} [2k,2k+1]
end{cases}
$$



[2] Not sure how to start or which one to pick.In either case i'm not sure if I have to take some sub sequence and then show it is finite and if so what's my logic and steps?










share|cite|improve this question



























    0














    [1] Are all simple functions Lebesgue Integrable? Prove or disprove.



    [2] If either $f_n longrightarrow f $ almost everywhere OR $f_n longrightarrow f$ in measure then show that f is finite valued (ie real valued) almost everywhere.



    MY ATTEMPT



    [1] I'm not sure if all simple functions are Lebesgue integrable or not but this is my example of a simple function which is not Lebesgue integrable



    Let $(mathbb{R},B_mathbb{R},mu_L)$ be a Lebesgue measure space and



    $phi:[0,infty] longrightarrow mathbb{R}$ is a simple function defined as



    $$
    phi(x)=
    begin{cases}
    -1, if x in bigcup_{x in mathbb{Z^+}} [2k+1,2k+2],\
    1, if x in bigcup_{x in mathbb{Z^+}} [2k,2k+1]
    end{cases}
    $$



    [2] Not sure how to start or which one to pick.In either case i'm not sure if I have to take some sub sequence and then show it is finite and if so what's my logic and steps?










    share|cite|improve this question

























      0












      0








      0







      [1] Are all simple functions Lebesgue Integrable? Prove or disprove.



      [2] If either $f_n longrightarrow f $ almost everywhere OR $f_n longrightarrow f$ in measure then show that f is finite valued (ie real valued) almost everywhere.



      MY ATTEMPT



      [1] I'm not sure if all simple functions are Lebesgue integrable or not but this is my example of a simple function which is not Lebesgue integrable



      Let $(mathbb{R},B_mathbb{R},mu_L)$ be a Lebesgue measure space and



      $phi:[0,infty] longrightarrow mathbb{R}$ is a simple function defined as



      $$
      phi(x)=
      begin{cases}
      -1, if x in bigcup_{x in mathbb{Z^+}} [2k+1,2k+2],\
      1, if x in bigcup_{x in mathbb{Z^+}} [2k,2k+1]
      end{cases}
      $$



      [2] Not sure how to start or which one to pick.In either case i'm not sure if I have to take some sub sequence and then show it is finite and if so what's my logic and steps?










      share|cite|improve this question













      [1] Are all simple functions Lebesgue Integrable? Prove or disprove.



      [2] If either $f_n longrightarrow f $ almost everywhere OR $f_n longrightarrow f$ in measure then show that f is finite valued (ie real valued) almost everywhere.



      MY ATTEMPT



      [1] I'm not sure if all simple functions are Lebesgue integrable or not but this is my example of a simple function which is not Lebesgue integrable



      Let $(mathbb{R},B_mathbb{R},mu_L)$ be a Lebesgue measure space and



      $phi:[0,infty] longrightarrow mathbb{R}$ is a simple function defined as



      $$
      phi(x)=
      begin{cases}
      -1, if x in bigcup_{x in mathbb{Z^+}} [2k+1,2k+2],\
      1, if x in bigcup_{x in mathbb{Z^+}} [2k,2k+1]
      end{cases}
      $$



      [2] Not sure how to start or which one to pick.In either case i'm not sure if I have to take some sub sequence and then show it is finite and if so what's my logic and steps?







      measure-theory convergence almost-everywhere measurable-functions






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Nov 21 '18 at 23:25









      Jason MooreJason Moore

      607




      607






















          1 Answer
          1






          active

          oldest

          votes


















          0














          [1] Think of a constant.



          [2] For the a.e. convergence, remember a convergent sequence is bounded. For the convergence in measure remember there is a subsequence converging a.e.






          share|cite|improve this answer





















          • Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
            – Jason Moore
            Nov 22 '18 at 0:40











          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%2f3008528%2fif-either-f-n-longrightarrow-f-almost-everywhere-or-f-n-longrightarrow-f%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














          [1] Think of a constant.



          [2] For the a.e. convergence, remember a convergent sequence is bounded. For the convergence in measure remember there is a subsequence converging a.e.






          share|cite|improve this answer





















          • Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
            – Jason Moore
            Nov 22 '18 at 0:40
















          0














          [1] Think of a constant.



          [2] For the a.e. convergence, remember a convergent sequence is bounded. For the convergence in measure remember there is a subsequence converging a.e.






          share|cite|improve this answer





















          • Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
            – Jason Moore
            Nov 22 '18 at 0:40














          0












          0








          0






          [1] Think of a constant.



          [2] For the a.e. convergence, remember a convergent sequence is bounded. For the convergence in measure remember there is a subsequence converging a.e.






          share|cite|improve this answer












          [1] Think of a constant.



          [2] For the a.e. convergence, remember a convergent sequence is bounded. For the convergence in measure remember there is a subsequence converging a.e.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 21 '18 at 23:31









          Will M.Will M.

          2,442314




          2,442314












          • Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
            – Jason Moore
            Nov 22 '18 at 0:40


















          • Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
            – Jason Moore
            Nov 22 '18 at 0:40
















          Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
          – Jason Moore
          Nov 22 '18 at 0:40




          Ok I get one but I'm still pretty lost in 2 mate. Anything else you can tell me?
          – Jason Moore
          Nov 22 '18 at 0:40


















          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%2f3008528%2fif-either-f-n-longrightarrow-f-almost-everywhere-or-f-n-longrightarrow-f%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

          How to fix TextFormField cause rebuild widget in Flutter

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