Why can we not establish the irrationality of Catalan's constant the same way as $zeta(3)$?












5












$begingroup$


One of the main ingredients in Apéry's proof of the irrationality of $zeta(3)$ is the existence of the fast-converging series:



$$
{displaystyle {begin{aligned}zeta (3)&={frac {5}{2}}sum _{k=1}^{infty }{frac {(-1)^{k-1}}{{binom {2k}{k}}k^{3}}}end{aligned}}}.
$$



Despite numerous attempts, no similar expressions were found for other values of the Riemann $zeta$-function at positive odd integers.



For Catalan's constant, however, we do have such an expression, namely:



$${displaystyle G={frac {pi }{8}}log left(2+{sqrt {3}}right)+{frac {3}{8}}sum _{n=0}^{infty }{frac {1}{(2n+1)^{2}{binom {2n}{n}}}}.}$$



Why is this not sufficient for applying an Apéry-like method for proving its irrationality?










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$endgroup$








  • 2




    $begingroup$
    Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
    $endgroup$
    – Dietrich Burde
    Oct 8 '18 at 12:42


















5












$begingroup$


One of the main ingredients in Apéry's proof of the irrationality of $zeta(3)$ is the existence of the fast-converging series:



$$
{displaystyle {begin{aligned}zeta (3)&={frac {5}{2}}sum _{k=1}^{infty }{frac {(-1)^{k-1}}{{binom {2k}{k}}k^{3}}}end{aligned}}}.
$$



Despite numerous attempts, no similar expressions were found for other values of the Riemann $zeta$-function at positive odd integers.



For Catalan's constant, however, we do have such an expression, namely:



$${displaystyle G={frac {pi }{8}}log left(2+{sqrt {3}}right)+{frac {3}{8}}sum _{n=0}^{infty }{frac {1}{(2n+1)^{2}{binom {2n}{n}}}}.}$$



Why is this not sufficient for applying an Apéry-like method for proving its irrationality?










share|cite|improve this question











$endgroup$








  • 2




    $begingroup$
    Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
    $endgroup$
    – Dietrich Burde
    Oct 8 '18 at 12:42
















5












5








5


4



$begingroup$


One of the main ingredients in Apéry's proof of the irrationality of $zeta(3)$ is the existence of the fast-converging series:



$$
{displaystyle {begin{aligned}zeta (3)&={frac {5}{2}}sum _{k=1}^{infty }{frac {(-1)^{k-1}}{{binom {2k}{k}}k^{3}}}end{aligned}}}.
$$



Despite numerous attempts, no similar expressions were found for other values of the Riemann $zeta$-function at positive odd integers.



For Catalan's constant, however, we do have such an expression, namely:



$${displaystyle G={frac {pi }{8}}log left(2+{sqrt {3}}right)+{frac {3}{8}}sum _{n=0}^{infty }{frac {1}{(2n+1)^{2}{binom {2n}{n}}}}.}$$



Why is this not sufficient for applying an Apéry-like method for proving its irrationality?










share|cite|improve this question











$endgroup$




One of the main ingredients in Apéry's proof of the irrationality of $zeta(3)$ is the existence of the fast-converging series:



$$
{displaystyle {begin{aligned}zeta (3)&={frac {5}{2}}sum _{k=1}^{infty }{frac {(-1)^{k-1}}{{binom {2k}{k}}k^{3}}}end{aligned}}}.
$$



Despite numerous attempts, no similar expressions were found for other values of the Riemann $zeta$-function at positive odd integers.



For Catalan's constant, however, we do have such an expression, namely:



$${displaystyle G={frac {pi }{8}}log left(2+{sqrt {3}}right)+{frac {3}{8}}sum _{n=0}^{infty }{frac {1}{(2n+1)^{2}{binom {2n}{n}}}}.}$$



Why is this not sufficient for applying an Apéry-like method for proving its irrationality?







irrational-numbers riemann-zeta irrationality-measure






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share|cite|improve this question













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edited Jan 21 at 17:12









Tito Piezas III

27.3k366174




27.3k366174










asked Oct 8 '18 at 12:37









KlangenKlangen

1,75811334




1,75811334








  • 2




    $begingroup$
    Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
    $endgroup$
    – Dietrich Burde
    Oct 8 '18 at 12:42
















  • 2




    $begingroup$
    Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
    $endgroup$
    – Dietrich Burde
    Oct 8 '18 at 12:42










2




2




$begingroup$
Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
$endgroup$
– Dietrich Burde
Oct 8 '18 at 12:42






$begingroup$
Having such an expression is by no means the same as irrationality. It is not clear how to adapt Apery's proof.
$endgroup$
– Dietrich Burde
Oct 8 '18 at 12:42












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