What exactly does it mean to multiply a vector by the transition matrix of a Markov process?












0












$begingroup$


I know that given a stationary distribution and 2 state transition matrix that



$begin{pmatrix}
Pi _{1} & Pi _{2}
end{pmatrix}begin{pmatrix}
P_{00} & P_{01}\
P_{10}& P_{11}
end{pmatrix}
=begin{pmatrix}
Pi_{1} &Pi_{2}
end{pmatrix}$



is true. But what exactly is the operation of multiplication by the transition matrix doing? And why is it that multiplying a vector that has its nth component made up of the probability that the state is in that nth position (i.e. the stationary distribution) gives you the same vector? What is special about it such that the multiplication operation gives the same output? Or am I mistaken in that multiplication by the transition matrix means nothing special outside of the stationary distribution/invariant vector?










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    I know that given a stationary distribution and 2 state transition matrix that



    $begin{pmatrix}
    Pi _{1} & Pi _{2}
    end{pmatrix}begin{pmatrix}
    P_{00} & P_{01}\
    P_{10}& P_{11}
    end{pmatrix}
    =begin{pmatrix}
    Pi_{1} &Pi_{2}
    end{pmatrix}$



    is true. But what exactly is the operation of multiplication by the transition matrix doing? And why is it that multiplying a vector that has its nth component made up of the probability that the state is in that nth position (i.e. the stationary distribution) gives you the same vector? What is special about it such that the multiplication operation gives the same output? Or am I mistaken in that multiplication by the transition matrix means nothing special outside of the stationary distribution/invariant vector?










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      I know that given a stationary distribution and 2 state transition matrix that



      $begin{pmatrix}
      Pi _{1} & Pi _{2}
      end{pmatrix}begin{pmatrix}
      P_{00} & P_{01}\
      P_{10}& P_{11}
      end{pmatrix}
      =begin{pmatrix}
      Pi_{1} &Pi_{2}
      end{pmatrix}$



      is true. But what exactly is the operation of multiplication by the transition matrix doing? And why is it that multiplying a vector that has its nth component made up of the probability that the state is in that nth position (i.e. the stationary distribution) gives you the same vector? What is special about it such that the multiplication operation gives the same output? Or am I mistaken in that multiplication by the transition matrix means nothing special outside of the stationary distribution/invariant vector?










      share|cite|improve this question









      $endgroup$




      I know that given a stationary distribution and 2 state transition matrix that



      $begin{pmatrix}
      Pi _{1} & Pi _{2}
      end{pmatrix}begin{pmatrix}
      P_{00} & P_{01}\
      P_{10}& P_{11}
      end{pmatrix}
      =begin{pmatrix}
      Pi_{1} &Pi_{2}
      end{pmatrix}$



      is true. But what exactly is the operation of multiplication by the transition matrix doing? And why is it that multiplying a vector that has its nth component made up of the probability that the state is in that nth position (i.e. the stationary distribution) gives you the same vector? What is special about it such that the multiplication operation gives the same output? Or am I mistaken in that multiplication by the transition matrix means nothing special outside of the stationary distribution/invariant vector?







      markov-chains markov-process stationary-processes






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Dec 3 '18 at 4:25









      user3491700user3491700

      535




      535






















          1 Answer
          1






          active

          oldest

          votes


















          1












          $begingroup$

          Given an initial distribution $pi$ (row vector) and the transition matrix $P$, the row vector $pi P$ contains the probabilities of ending up in the $2$ states after one step, if the initial state follows the initial distribution. More generally, $pi P^n$ contains the probabilities of ending up in the $2$ states after $n$ steps, if starting according to the initial distribution.



          If $pi$ is a stationary distribution, then $pi P^n = pi$, which means that after any number of steps, the distribution of the state you land on is the same as the initial distribution.






          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%2f3023627%2fwhat-exactly-does-it-mean-to-multiply-a-vector-by-the-transition-matrix-of-a-mar%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









            1












            $begingroup$

            Given an initial distribution $pi$ (row vector) and the transition matrix $P$, the row vector $pi P$ contains the probabilities of ending up in the $2$ states after one step, if the initial state follows the initial distribution. More generally, $pi P^n$ contains the probabilities of ending up in the $2$ states after $n$ steps, if starting according to the initial distribution.



            If $pi$ is a stationary distribution, then $pi P^n = pi$, which means that after any number of steps, the distribution of the state you land on is the same as the initial distribution.






            share|cite|improve this answer









            $endgroup$


















              1












              $begingroup$

              Given an initial distribution $pi$ (row vector) and the transition matrix $P$, the row vector $pi P$ contains the probabilities of ending up in the $2$ states after one step, if the initial state follows the initial distribution. More generally, $pi P^n$ contains the probabilities of ending up in the $2$ states after $n$ steps, if starting according to the initial distribution.



              If $pi$ is a stationary distribution, then $pi P^n = pi$, which means that after any number of steps, the distribution of the state you land on is the same as the initial distribution.






              share|cite|improve this answer









              $endgroup$
















                1












                1








                1





                $begingroup$

                Given an initial distribution $pi$ (row vector) and the transition matrix $P$, the row vector $pi P$ contains the probabilities of ending up in the $2$ states after one step, if the initial state follows the initial distribution. More generally, $pi P^n$ contains the probabilities of ending up in the $2$ states after $n$ steps, if starting according to the initial distribution.



                If $pi$ is a stationary distribution, then $pi P^n = pi$, which means that after any number of steps, the distribution of the state you land on is the same as the initial distribution.






                share|cite|improve this answer









                $endgroup$



                Given an initial distribution $pi$ (row vector) and the transition matrix $P$, the row vector $pi P$ contains the probabilities of ending up in the $2$ states after one step, if the initial state follows the initial distribution. More generally, $pi P^n$ contains the probabilities of ending up in the $2$ states after $n$ steps, if starting according to the initial distribution.



                If $pi$ is a stationary distribution, then $pi P^n = pi$, which means that after any number of steps, the distribution of the state you land on is the same as the initial distribution.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Dec 3 '18 at 4:36









                angryavianangryavian

                40.4k23280




                40.4k23280






























                    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%2f3023627%2fwhat-exactly-does-it-mean-to-multiply-a-vector-by-the-transition-matrix-of-a-mar%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

                    Le Mesnil-Réaume

                    Ida-Boy-Ed-Garten

                    web3.py web3.isConnected() returns false always