The evaluation of the Riemann zeta function at odd integers remains an important analytical problem, partly because many of its classical series representations converge slowly. In this paper, we develop a continuous filtering framework for analyzing weighted series representations associated with $ \zeta(5) $. Rather than relying on closed-form algebraic transformations, the proposed approach introduces analytically designed weighting sequences (filters) within a continuous integral formulation. We show that this construction naturally interprets discrete filtering as a continuous transformation of the underlying integral kernel. Furthermore, the proposed framework reveals a fundamental trade-off between convergence enhancement and preservation of the kernel structure. By establishing a continuous–discrete connection, the framework provides a unified perspective for studying filtered series representations and offers new insight into the analytical structure of zeta-related series.
Citation: Sunyoung Bu, Jongkyum Kwon. Continuous filtering and kernel transformations in series representations of $ \zeta(5) $[J]. Electronic Research Archive, 2026, 34(11): 8101-8118. doi: 10.3934/era.2026345
The evaluation of the Riemann zeta function at odd integers remains an important analytical problem, partly because many of its classical series representations converge slowly. In this paper, we develop a continuous filtering framework for analyzing weighted series representations associated with $ \zeta(5) $. Rather than relying on closed-form algebraic transformations, the proposed approach introduces analytically designed weighting sequences (filters) within a continuous integral formulation. We show that this construction naturally interprets discrete filtering as a continuous transformation of the underlying integral kernel. Furthermore, the proposed framework reveals a fundamental trade-off between convergence enhancement and preservation of the kernel structure. By establishing a continuous–discrete connection, the framework provides a unified perspective for studying filtered series representations and offers new insight into the analytical structure of zeta-related series.
| [1] |
J. M. Borwein, D. M. Bradley, R. E. Crandall, Computational strategies for the Riemann zeta function, J. Comput. Appl. Math., 121 (2000), 247–296. https://doi.org/10.1016/S0377-0427(00)00336-8 doi: 10.1016/S0377-0427(00)00336-8
|
| [2] | P. Flajolet, I. Vardi, Zeta function expansions of classical constants, 1996. Available from: https://algo.inria.fr/flajolet/Publications/FlVa96.pdf. |
| [3] | E. C. Titchmarsh, The Theory of the Riemann Zeta-Function, 2$^{nd}$ edition, Oxford University Press, 1986. |
| [4] | R. Apéry, Irrationalité de $\zeta(2)$ et $\zeta(3)$, Astérisque, 61 (1979), 11–13. |
| [5] |
V. V. Zudilin, A third-order Apéry-like recursion for $\zeta(5)$, Math. Notes, 72 (2002), 733–737. https://doi.org/10.1023/A:1021473409544 doi: 10.1023/A:1021473409544
|
| [6] |
B. Beckermann, G. Labahn, Effective computation of rational approximants and interpolants, Reliab. Comput., 6 (2000), 365–390. https://doi.org/10.1023/A:1009942122633 doi: 10.1023/A:1009942122633
|
| [7] |
A. Soria-Lorente, On Zudilin-like rational approximations to $\zeta(5)$, Notes Number Theory Discrete Math., 24 (2018), 104–116. https://doi.org/10.7546/nntdm.2018.24.2.104-116 doi: 10.7546/nntdm.2018.24.2.104-116
|
| [8] |
W. V. Zudilin, One of the numbers $\zeta(5), \zeta(7), \zeta(9), \zeta(11)$ is irrational, Russ. Math. Surv., 56 (2001), 774–776. https://doi.org/10.1070/RM2001v056n04ABEH000427 doi: 10.1070/RM2001v056n04ABEH000427
|
| [9] |
T. Amdeberhan, D. Zeilberger, Hypergeometric series acceleration via the WZ method, Electron. J. Comb., 4 (1996), R3. https://doi.org/10.37236/1318 doi: 10.37236/1318
|
| [10] |
E. J. Weniger, Nonlinear sequence transformations for the acceleration of convergence and the summation of divergent series, Comput. Phys. Rep., 10 (1989), 189–371. https://doi.org/10.1016/0167-7977(89)90011-7 doi: 10.1016/0167-7977(89)90011-7
|
| [11] |
W. Zudilin, Arithmetic of linear forms involving odd zeta values, J. Theor. Nombres Bordeaux, 16 (2004), 251–291. https://doi.org/10.5802/jtnb.447 doi: 10.5802/jtnb.447
|
| [12] |
D. Cvijović, J. Klinowski, Integral representations of the Riemann zeta function for odd integer arguments, J. Comput. Appl. Math., 142 (2002), 435–439. https://doi.org/10.1016/S0377-0427(02)00358-8 doi: 10.1016/S0377-0427(02)00358-8
|
| [13] | E. A. Galapon, Finite-part integral representation of the Riemann zeta function at odd positive integers and consequent representations, preprint, arXiv: 2203.11342. |
| [14] | T. M. Apostol, Modular Functions and Dirichlet Series in Number Theory, Springer-Verlag, 1976. https://doi.org/10.1007/978-1-4684-9910-0 |
| [15] | F. W. J. Olver, D. W. Lozier, R. F. Boisvert, C. W. Clark, The NIST Handbook of Mathematical Functions, Cambridge University Press, 2010. |