A proper definition of recurrent event in probability












0














I am having hard time understanding the definition of a recurrent event in probability context.



At our lecture it was defined as follows:



Let $X^{[i,n]} = {X_i, ldots, X_n}$ be a random sequence. The random variables $X_j$ can attain countably many values. An event $epsilon$ that appears on the $n$-th and the $m+n$-th place of sequence $X^{[1,m+n]}$ is called recurrent if and only if it occurs on the last place of the sequence $X^{[1,n]}$ and on the last place of the sequence $X^{[n+1,n+m]}$.
Then $Prob(X^{[1,n+m]}) = Prob(X^{[1,n]})cdot Prob(X^{[n+1,n+m]})$.



An event $epsilon$ could be for example the event when $S_n = sum_{j=i}^nX_j = 0$.



The variables $X_i$ may be dependent in some way. It is clear that the multiplication rule holds if the events are independent. However, I do not understand, why the multiplication rule should apply in general.
Is it possible, that the event is recurrent if the multiplication rule applies?



The closest definition I could find online to what we defined in the lecture can be seen on this webpage. It is probably more exact, but I really struggle tu wrap my head around it.



Could anyone please explain, why the multiplication rule holds for recurrent events and potentialy elaborate on the definition from the link? Any help would be very appreciated!










share|cite|improve this question





























    0














    I am having hard time understanding the definition of a recurrent event in probability context.



    At our lecture it was defined as follows:



    Let $X^{[i,n]} = {X_i, ldots, X_n}$ be a random sequence. The random variables $X_j$ can attain countably many values. An event $epsilon$ that appears on the $n$-th and the $m+n$-th place of sequence $X^{[1,m+n]}$ is called recurrent if and only if it occurs on the last place of the sequence $X^{[1,n]}$ and on the last place of the sequence $X^{[n+1,n+m]}$.
    Then $Prob(X^{[1,n+m]}) = Prob(X^{[1,n]})cdot Prob(X^{[n+1,n+m]})$.



    An event $epsilon$ could be for example the event when $S_n = sum_{j=i}^nX_j = 0$.



    The variables $X_i$ may be dependent in some way. It is clear that the multiplication rule holds if the events are independent. However, I do not understand, why the multiplication rule should apply in general.
    Is it possible, that the event is recurrent if the multiplication rule applies?



    The closest definition I could find online to what we defined in the lecture can be seen on this webpage. It is probably more exact, but I really struggle tu wrap my head around it.



    Could anyone please explain, why the multiplication rule holds for recurrent events and potentialy elaborate on the definition from the link? Any help would be very appreciated!










    share|cite|improve this question



























      0












      0








      0







      I am having hard time understanding the definition of a recurrent event in probability context.



      At our lecture it was defined as follows:



      Let $X^{[i,n]} = {X_i, ldots, X_n}$ be a random sequence. The random variables $X_j$ can attain countably many values. An event $epsilon$ that appears on the $n$-th and the $m+n$-th place of sequence $X^{[1,m+n]}$ is called recurrent if and only if it occurs on the last place of the sequence $X^{[1,n]}$ and on the last place of the sequence $X^{[n+1,n+m]}$.
      Then $Prob(X^{[1,n+m]}) = Prob(X^{[1,n]})cdot Prob(X^{[n+1,n+m]})$.



      An event $epsilon$ could be for example the event when $S_n = sum_{j=i}^nX_j = 0$.



      The variables $X_i$ may be dependent in some way. It is clear that the multiplication rule holds if the events are independent. However, I do not understand, why the multiplication rule should apply in general.
      Is it possible, that the event is recurrent if the multiplication rule applies?



      The closest definition I could find online to what we defined in the lecture can be seen on this webpage. It is probably more exact, but I really struggle tu wrap my head around it.



      Could anyone please explain, why the multiplication rule holds for recurrent events and potentialy elaborate on the definition from the link? Any help would be very appreciated!










      share|cite|improve this question















      I am having hard time understanding the definition of a recurrent event in probability context.



      At our lecture it was defined as follows:



      Let $X^{[i,n]} = {X_i, ldots, X_n}$ be a random sequence. The random variables $X_j$ can attain countably many values. An event $epsilon$ that appears on the $n$-th and the $m+n$-th place of sequence $X^{[1,m+n]}$ is called recurrent if and only if it occurs on the last place of the sequence $X^{[1,n]}$ and on the last place of the sequence $X^{[n+1,n+m]}$.
      Then $Prob(X^{[1,n+m]}) = Prob(X^{[1,n]})cdot Prob(X^{[n+1,n+m]})$.



      An event $epsilon$ could be for example the event when $S_n = sum_{j=i}^nX_j = 0$.



      The variables $X_i$ may be dependent in some way. It is clear that the multiplication rule holds if the events are independent. However, I do not understand, why the multiplication rule should apply in general.
      Is it possible, that the event is recurrent if the multiplication rule applies?



      The closest definition I could find online to what we defined in the lecture can be seen on this webpage. It is probably more exact, but I really struggle tu wrap my head around it.



      Could anyone please explain, why the multiplication rule holds for recurrent events and potentialy elaborate on the definition from the link? Any help would be very appreciated!







      probability probability-theory stochastic-processes recurrence-relations random-walk






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 4 at 19:20







      Jan Vainer

















      asked Jan 4 at 18:39









      Jan VainerJan Vainer

      206




      206






















          0






          active

          oldest

          votes











          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%2f3061953%2fa-proper-definition-of-recurrent-event-in-probability%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          0






          active

          oldest

          votes








          0






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          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%2f3061953%2fa-proper-definition-of-recurrent-event-in-probability%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

          An IMO inspired problem

          Management

          Has there ever been an instance of an active nuclear power plant within or near a war zone?