In mathematics, Catalan's constant G, is defined by
where β is the Dirichlet beta function. Its numerical value[1] is approximately (sequence A006752 in the OEIS)
- G = 0.915965594177219015054603514932384110774…
Unsolved problem in mathematics:
Is Catalan's constant irrational? If so, is it transcendental?
It is not known whether G is irrational, let alone transcendental.[2] G has been called "arguably the most basic constant whose irrationality and transcendence (though strongly
suspected) remain unproven".[3]
Catalan's constant was named after Eugène Charles Catalan, who found quickly-converging series for its calculation and published a memoir on it in 1865.[4][5]
In low-dimensional topology, Catalan's constant is 1/4 of the volume of an ideal hyperbolic octahedron, and therefore 1/4 of the hyperbolic volume of the complement of the Whitehead link.[6] It is 1/8 of the volume of the complement of the Borromean rings.[7]
In combinatorics and statistical mechanics, it arises in connection with counting domino tilings,[8] spanning trees,[9] and Hamiltonian cycles of grid graphs.[10]
In number theory, Catalan's constant appears in a conjectured formula for the asymptotic number of primes of the form according to Hardy and Littlewood's Conjecture F. However, it is an unsolved problem (one of Landau's problems) whether there are even infinitely many primes of this form.[11]
Catalan's constant also appears in the calculation of the mass distribution of spiral galaxies.[12][13]
As Seán Stewart writes, "There is a rich and seemingly endless source of definite integrals that
can be equated to or expressed in terms of Catalan's constant."[14] Some of these expressions include:
where the last three formulas are related to Malmsten's integrals.[15]
If K(k) is the complete elliptic integral of the first kind, as a function of the elliptic modulus k, then
If E(k) is the complete elliptic integral of the second kind, as a function of the elliptic modulus k, then
With the gamma function Γ(x + 1) = x!
The integral
is a known special function, called the inverse tangent integral, and was extensively studied by Srinivasa Ramanujan.
G appears in values of the second polygamma function, also called the trigamma function, at fractional arguments:
Simon Plouffe gives an infinite collection of identities between the trigamma function, π2 and Catalan's constant; these are expressible as paths on a graph.
Catalan's constant occurs frequently in relation to the Clausen function, the inverse tangent integral, the inverse sine integral, the Barnes G-function, as well as integrals and series summable in terms of the aforementioned functions.
As a particular example, by first expressing the inverse tangent integral in its closed form – in terms of Clausen functions – and then expressing those Clausen functions in terms of the Barnes G-function, the following expression is obtained (see Clausen function for more):
If one defines the Lerch transcendent Φ(z,s,α) (related to the Lerch zeta function) by
then
The number of known digits of Catalan's constant G has increased dramatically during the last decades. This is due both to the increase of performance of computers as well as to algorithmic improvements.[23]
More information Date, Decimal digits ...
Number of known decimal digits of Catalan's constant G
Date | Decimal digits | Computation performed by |
1832 | 16 | Thomas Clausen |
1858 | 19 | Carl Johan Danielsson Hill |
1864 | 14 | Eugène Charles Catalan |
1877 | 20 | James W. L. Glaisher |
1913 | 32 | James W. L. Glaisher |
1990 | 20000 | Greg J. Fee |
1996 | 50000 | Greg J. Fee |
August 14, 1996 | 100000 | Greg J. Fee & Simon Plouffe |
September 29, 1996 | 300000 | Thomas Papanikolaou |
1996 | 1500000 | Thomas Papanikolaou |
1997 | 3379957 | Patrick Demichel |
January 4, 1998 | 12500000 | Xavier Gourdon |
2001 | 100000500 | Xavier Gourdon & Pascal Sebah |
2002 | 201000000 | Xavier Gourdon & Pascal Sebah |
October 2006 | 5000000000 | Shigeru Kondo & Steve Pagliarulo[24] |
August 2008 | 10000000000 | Shigeru Kondo & Steve Pagliarulo[23] |
January 31, 2009 | 15510000000 | Alexander J. Yee & Raymond Chan[25] |
April 16, 2009 | 31026000000 | Alexander J. Yee & Raymond Chan[25] |
June 7, 2015 | 200000001100 | Robert J. Setti[26] |
April 12, 2016 | 250000000000 | Ron Watkins[26] |
February 16, 2019 | 300000000000 | Tizian Hanselmann[26] |
March 29, 2019 | 500000000000 | Mike A & Ian Cutress[26] |
July 16, 2019 | 600000000100 | Seungmin Kim[27][28] |
September 6, 2020 | 1000000001337 | Andrew Sun[29] |
March 9, 2022 | 1200000000100 | Seungmin Kim[29] |
Close
Catalan, E. (1865). "Mémoire sur la transformation des séries et sur quelques intégrales définies". Ers, Publiés Par l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique. Collection in 4. Mémoires de l'Académie royale des sciences, des lettres et des beaux-arts de Belgique (in French). 33. Brussels. hdl:2268/193841.
Broadhurst, D. J. (1998). "Polylogarithmic ladders, hypergeometric series and the ten millionth digits of ζ(3) and ζ(5)". arXiv:math.CA/9803067.
Karatsuba, E. A. (1991). "Fast evaluation of transcendental functions". Probl. Inf. Transm. 27 (4): 339–360. MR 1156939. Zbl 0754.65021.
- Adamchik, Victor (2002). "A certain series associated with Catalan's constant". Zeitschrift für Analysis und ihre Anwendungen. 21 (3): 1–10. doi:10.4171/ZAA/1110. MR 1929434. Archived from the original on 2010-03-16. Retrieved 2005-07-14.
- Fee, Gregory J. (1990). "Computation of Catalan's Constant Using Ramanujan's Formula". In Watanabe, Shunro; Nagata, Morio (eds.). Proceedings of the International Symposium on Symbolic and Algebraic Computation, ISSAC '90, Tokyo, Japan, August 20-24, 1990. ACM. pp. 157–160. doi:10.1145/96877.96917. ISBN 0201548925. S2CID 1949187.
- Bradley, David M. (1999). "A class of series acceleration formulae for Catalan's constant". The Ramanujan Journal. 3 (2): 159–173. arXiv:0706.0356. Bibcode:2007arXiv0706.0356B. doi:10.1023/A:1006945407723. MR 1703281. S2CID 5111792.
- Adamchik, Victor. "33 representations for Catalan's constant". Archived from the original on 2016-08-07. Retrieved 14 July 2005.
- Plouffe, Simon (1993). "A few identities (III) with Catalan". Archived from the original on 2019-06-26. Retrieved 29 July 2005. (Provides over one hundred different identities).
- Plouffe, Simon (1999). "A few identities with Catalan constant and Pi^2". Archived from the original on 2019-06-26. Retrieved 29 July 2005. (Provides a graphical interpretation of the relations)
- Fee, Greg (1996). Catalan's Constant (Ramanujan's Formula). (Provides the first 300,000 digits of Catalan's constant)
- Bradley, David M. (2001). Representations of Catalan's constant. CiteSeerX 10.1.1.26.1879.
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- Johansson, Fredrik. "0.915965594177219015054603514932". Ordner, a catalog of real numbers in Fungrim. Retrieved 21 April 2021.
- "Catalan's Constant". YouTube. Let's Learn, Nemo!. 10 August 2020. Retrieved 6 April 2021.
- Weisstein, Eric W. "Catalan's Constant". MathWorld.
- "Catalan constant: Series representations". Wolfram Functions Site.
- "Catalan constant". Encyclopedia of Mathematics. EMS Press. 2001 [1994].
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