Unclear on step #2 of the MathWorld definition of the Reimann Prime Counting Function











up vote
0
down vote

favorite
1












I was reading through the MathWorld article on the Reimann Prime Counting Function.



The first step in the definition is clear to me:



$$f(x) = sum_{p^v < x text{ and p prime}} frac{1}{v}$$



Here is the second step:



$$=sum_{n}frac{pi(x^{1/n})}{n}$$



It is not clear to me how the sum of the reciprocal of the power is equal to the sum of the prime counting function divided by all values of $n$.



I would appreciate if someone could show how the second step follows from the first.










share|cite|improve this question


























    up vote
    0
    down vote

    favorite
    1












    I was reading through the MathWorld article on the Reimann Prime Counting Function.



    The first step in the definition is clear to me:



    $$f(x) = sum_{p^v < x text{ and p prime}} frac{1}{v}$$



    Here is the second step:



    $$=sum_{n}frac{pi(x^{1/n})}{n}$$



    It is not clear to me how the sum of the reciprocal of the power is equal to the sum of the prime counting function divided by all values of $n$.



    I would appreciate if someone could show how the second step follows from the first.










    share|cite|improve this question
























      up vote
      0
      down vote

      favorite
      1









      up vote
      0
      down vote

      favorite
      1






      1





      I was reading through the MathWorld article on the Reimann Prime Counting Function.



      The first step in the definition is clear to me:



      $$f(x) = sum_{p^v < x text{ and p prime}} frac{1}{v}$$



      Here is the second step:



      $$=sum_{n}frac{pi(x^{1/n})}{n}$$



      It is not clear to me how the sum of the reciprocal of the power is equal to the sum of the prime counting function divided by all values of $n$.



      I would appreciate if someone could show how the second step follows from the first.










      share|cite|improve this question













      I was reading through the MathWorld article on the Reimann Prime Counting Function.



      The first step in the definition is clear to me:



      $$f(x) = sum_{p^v < x text{ and p prime}} frac{1}{v}$$



      Here is the second step:



      $$=sum_{n}frac{pi(x^{1/n})}{n}$$



      It is not clear to me how the sum of the reciprocal of the power is equal to the sum of the prime counting function divided by all values of $n$.



      I would appreciate if someone could show how the second step follows from the first.







      prime-numbers proof-explanation






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Nov 19 at 17:00









      Larry Freeman

      3,24721239




      3,24721239






















          1 Answer
          1






          active

          oldest

          votes

















          up vote
          1
          down vote



          accepted










          Hint:



          How many $v$-th powers of primes are there between $1$ and $x$?



          Answer: if $p$ is a prime then $p^v<x$ iff $p<x^{1/v}$. Then the number of $v$-th powers of primes between $1$ and $x$ is $pi(x^{1/v})$.






          share|cite|improve this answer























          • the product of these numbers is the least common multiple of $x$.
            – Larry Freeman
            Nov 19 at 17:09












          • Now, I am clear. Thanks!
            – Larry Freeman
            Nov 19 at 23:54











          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%2f3005185%2funclear-on-step-2-of-the-mathworld-definition-of-the-reimann-prime-counting-fun%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








          up vote
          1
          down vote



          accepted










          Hint:



          How many $v$-th powers of primes are there between $1$ and $x$?



          Answer: if $p$ is a prime then $p^v<x$ iff $p<x^{1/v}$. Then the number of $v$-th powers of primes between $1$ and $x$ is $pi(x^{1/v})$.






          share|cite|improve this answer























          • the product of these numbers is the least common multiple of $x$.
            – Larry Freeman
            Nov 19 at 17:09












          • Now, I am clear. Thanks!
            – Larry Freeman
            Nov 19 at 23:54















          up vote
          1
          down vote



          accepted










          Hint:



          How many $v$-th powers of primes are there between $1$ and $x$?



          Answer: if $p$ is a prime then $p^v<x$ iff $p<x^{1/v}$. Then the number of $v$-th powers of primes between $1$ and $x$ is $pi(x^{1/v})$.






          share|cite|improve this answer























          • the product of these numbers is the least common multiple of $x$.
            – Larry Freeman
            Nov 19 at 17:09












          • Now, I am clear. Thanks!
            – Larry Freeman
            Nov 19 at 23:54













          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          Hint:



          How many $v$-th powers of primes are there between $1$ and $x$?



          Answer: if $p$ is a prime then $p^v<x$ iff $p<x^{1/v}$. Then the number of $v$-th powers of primes between $1$ and $x$ is $pi(x^{1/v})$.






          share|cite|improve this answer














          Hint:



          How many $v$-th powers of primes are there between $1$ and $x$?



          Answer: if $p$ is a prime then $p^v<x$ iff $p<x^{1/v}$. Then the number of $v$-th powers of primes between $1$ and $x$ is $pi(x^{1/v})$.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Nov 19 at 17:12

























          answered Nov 19 at 17:05









          ajotatxe

          52.3k23789




          52.3k23789












          • the product of these numbers is the least common multiple of $x$.
            – Larry Freeman
            Nov 19 at 17:09












          • Now, I am clear. Thanks!
            – Larry Freeman
            Nov 19 at 23:54


















          • the product of these numbers is the least common multiple of $x$.
            – Larry Freeman
            Nov 19 at 17:09












          • Now, I am clear. Thanks!
            – Larry Freeman
            Nov 19 at 23:54
















          the product of these numbers is the least common multiple of $x$.
          – Larry Freeman
          Nov 19 at 17:09






          the product of these numbers is the least common multiple of $x$.
          – Larry Freeman
          Nov 19 at 17:09














          Now, I am clear. Thanks!
          – Larry Freeman
          Nov 19 at 23:54




          Now, I am clear. Thanks!
          – Larry Freeman
          Nov 19 at 23:54


















          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%2f3005185%2funclear-on-step-2-of-the-mathworld-definition-of-the-reimann-prime-counting-fun%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

          Aardman Animations

          Are they similar matrix

          “minimization” problem in Euclidean space related to orthonormal basis