Precise Asymptotics and Exact Formulas for Tensor Product Energies of Fibonacci Lattices
Pith reviewed 2026-05-21 02:42 UTC · model grok-4.3
The pith
Sums appearing in Fibonacci lattice energies grow linearly in the index n plus a constant, with exponentially small remainder, and admit exact closed forms in special cases.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The sum (1 over F_n to the sigma) times the double sum over m of f(m over F_n) over absolute sin of pi m over F_n to the sigma, times the analogous term with F_{n-1} m, behaves for large n like C n plus D plus an error bounded by a geometric term (1 minus epsilon) to the n. The leading coefficients C and D are given by explicit series involving values of the Dedekind zeta function attached to Q(sqrt 5). When f is identically one and sigma equals two the sum collapses exactly to (4n over 75) F_{2n} minus (17 over 225) F_n squared minus (-1)^n times (2 over 15) minus one over nine.
What carries the argument
Decomposition of the sum that exploits the linear recurrence of the Fibonacci sequence together with the algebraic integers in the ring of Q(sqrt 5) to isolate the linear growth and to express the constant term via zeta-series.
If this is right
- The energy of the Fibonacci lattice point set therefore increases exactly linearly with the Fibonacci index.
- The leading coefficient C can be evaluated to arbitrary precision by summing the associated zeta series.
- Exact polynomial expressions in Fibonacci numbers become available for certain choices of f and sigma.
- The exponentially small error term implies that truncation after the linear and constant terms already gives high-accuracy approximations for moderate n.
Where Pith is reading between the lines
- The same recurrence-plus-zeta technique may extend to other quadratic irrational rotations or to higher-dimensional product lattices built from Fibonacci sequences.
- Because the error decays exponentially, these formulas could supply rigorous a-priori error bounds for quasi-Monte Carlo integration rules that use Fibonacci points.
- The appearance of the Dedekind zeta function suggests a hidden arithmetic symmetry that might be visible in the distribution of the sine products themselves.
Load-bearing premise
The test functions f must be regular enough that the sum splits cleanly according to the Fibonacci recurrence without extra boundary or approximation errors.
What would settle it
Compute the sum numerically for n around 30 with sigma equal to 2 and f equal to one; the exact closed-form formula must hold to machine precision, and for general regular f the remainder after subtracting the predicted linear term must fall below 10 to the minus 5.
Figures
read the original abstract
We consider the asymptotics of sums of the form $$ \frac1{F_n^\sigma} \sum_{m = 1}^{F_n-1} \frac{f(m/F_n)}{\left|{\sin(\pi m/F_n)}\right|^\sigma} \frac{f(F_{n-1}m/F_n)}{\left|{\sin(\pi F_{n-1}m/F_n)}\right|^\sigma} $$ where $(F_n)_{n \in \mathbb N} = (1, 1, 2, 3, 5, 8, 13, \dots)$ are the Fibonacci numbers. Such sums appear, for example, in the context of discrepancy theory and numerical integration methods reformulated as energy minimization problems. We show that for parameters $\sigma > 1$ and a large class of functions $f$ the above sum behaves asymptotically like $$ C n + D + O\left((1-\varepsilon)^{n}\right) $$ for some constants $C$ and $D$. These constants can be given via infinite series connected to the Dedekind zeta function over the algebraic number field $\mathbb Q(\sqrt5)$. In special cases we even observe simple closed-form expressions for such sums as above, explicitly proving that $$ \sum_{m=1}^{F_n-1} \frac1{\sin(\pi m/F_n)^2} \frac1{\sin(\pi F_{n-1} m/F_n)^2} = \frac{4n}{75} F_{2n} - \frac{17}{225}F_n^2 - (-1)^n \frac2{15} - \frac19. $$
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper examines the asymptotic behavior of the normalized sum (1/F_n^σ) ∑_{m=1}^{F_n-1} [f(m/F_n)/|sin(π m/F_n)|^σ] [f(F_{n-1} m/F_n)/|sin(π F_{n-1} m/F_n)|^σ] for Fibonacci numbers F_n, σ > 1, and a class of functions f. It claims this sum equals C n + D + O((1-ε)^n) for constants C, D given by convergent series tied to the Dedekind zeta function of Q(√5). For the special case σ=2 and f≡1, it proves the exact identity ∑_{m=1}^{F_n-1} 1/sin(π m/F_n)^2 * 1/sin(π F_{n-1} m/F_n)^2 = (4n/75) F_{2n} - (17/225) F_n^2 - (-1)^n (2/15) - 1/9.
Significance. If the derivations hold, the work supplies precise asymptotics with exponential error for tensor-product energies on Fibonacci lattices, directly linking the leading coefficients to the Dedekind zeta function of Q(√5) via independent series. The explicit closed-form identity for the special case is a clear strength, as both sides are elementary and verifiable for each n, supporting applications in discrepancy theory and energy minimization.
major comments (2)
- [Main asymptotic result] Main asymptotic theorem (statement following the abstract and developed in the body): the decomposition of the sum via the Fibonacci recurrence and the ring of integers of Q(√5) is load-bearing for both the linear term C n and the exponential error; the manuscript must explicitly identify the precise regularity class on f (e.g., C^1 or Fourier-coefficient decay) that guarantees the error bound is uniform in that class.
- [Exact formula for σ=2, f=1] Special-case identity (displayed in the abstract and proved in the relevant section): while the closed form is elementary and checkable, the proof should include a direct verification step for small n (e.g., n=3,4) to confirm the coefficients 4/75, 17/225, etc., before invoking the general recurrence argument.
minor comments (2)
- [Abstract] The abstract refers to 'a large class of functions f' without definition; move the precise statement of the regularity hypothesis to the introduction or the statement of the main theorem.
- [Definition of C and D] Notation for the constants C and D: explicitly label the infinite series expressions in terms of the Dedekind zeta function so that readers can see they are independent of the original sum.
Simulated Author's Rebuttal
We thank the referee for the careful reading, positive evaluation, and recommendation of minor revision. We address each major comment below.
read point-by-point responses
-
Referee: [Main asymptotic result] Main asymptotic theorem (statement following the abstract and developed in the body): the decomposition of the sum via the Fibonacci recurrence and the ring of integers of Q(√5) is load-bearing for both the linear term C n and the exponential error; the manuscript must explicitly identify the precise regularity class on f (e.g., C^1 or Fourier-coefficient decay) that guarantees the error bound is uniform in that class.
Authors: We agree that an explicit regularity class on f is necessary to make the uniformity of the O((1-ε)^n) error bound fully rigorous. The current manuscript refers to 'a large class of functions f' without a precise definition. In the revised version we will add the following statement to the main theorem: f is C^1 on the circle with ||f'||_∞ bounded and Fourier coefficients satisfying |ˆf(k)| ≤ C/|k|^2. This class is sufficient for the Fibonacci-recurrence decomposition and the estimates that connect the leading coefficients to the Dedekind zeta function of Q(√5). revision: yes
-
Referee: [Exact formula for σ=2, f=1] Special-case identity (displayed in the abstract and proved in the relevant section): while the closed form is elementary and checkable, the proof should include a direct verification step for small n (e.g., n=3,4) to confirm the coefficients 4/75, 17/225, etc., before invoking the general recurrence argument.
Authors: We accept the suggestion. The proof currently proceeds directly from the recurrence relation satisfied by the sums. In the revised manuscript we will insert an explicit verification subsection that computes both sides of the identity for n=3 and n=4 by direct summation (using the known values of F_3=2, F_4=3, F_5=5, F_6=8, F_7=13, F_8=21) and confirms that the numerical values match the closed-form expression with the stated coefficients 4/75, 17/225, etc. This check precedes the general recurrence argument. revision: yes
Circularity Check
No significant circularity identified
full rationale
The derivation decomposes the normalized double sum using the linear recurrence of the Fibonacci sequence and the algebraic structure of the ring of integers in Q(√5). Leading coefficients C and D are expressed as independent convergent series attached to the Dedekind zeta function of that field; these series are not defined in terms of the target sum. The exponential error bound follows from the contraction |φ^{-2}| < 1. The special-case closed-form identity is an explicit polynomial expression in n, F_n and F_{2n} that is asserted to hold identically for integer n ≥ 2 and is therefore directly verifiable without reference to the asymptotic analysis. No load-bearing step reduces a claimed result to a fitted parameter, self-citation, or input by construction.
Axiom & Free-Parameter Ledger
axioms (2)
- standard math The Fibonacci sequence satisfies the recurrence F_n = F_{n-1} + F_{n-2} with initial conditions F_1=1, F_2=1.
- standard math Analytic continuation and functional equation properties of the Dedekind zeta function over the quadratic field Q(√5).
Lean theorems connected to this paper
-
IndisputableMonolith/Constants and Foundation/AlphaDerivationExplicitphi_golden_ratio, phi_fixed_point echoes?
echoesECHOES: this paper passage has the same mathematical shape or conceptual pattern as the Recognition theorem, but is not a direct formal dependency.
ϕ = (1+√5)/2 ... Wi,k = 1/√5 (w+(i) ϕ^k - w-(i) (-1/ϕ)^k) ... ζ_{Q(√5)}(σ) = ∑ 1/η_i^σ ... C = 2 f(0)^2 5^{σ/2} / π^{2σ} ζ_{Q(√5)}(σ)
-
IndisputableMonolith/Foundation/ArithmeticFromLogicembed_strictMono_of_one_lt refines?
refinesRelation between the paper passage and the cited Recognition theorem.
error O(n² ϕ^{-β n/2}) with β = min{α,σ-1} ... contraction from |φ^{-2}|<1
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
- [1]
-
[2]
Tom M. Apostol. Theorems on generalized Dedekind sums.Pacific J. Math., 2:1–9, 1952
work page 1952
-
[3]
Springer Monographs in Mathematics
J´ ozsef Beck.Probabilistic Diophantine approximation. Springer Monographs in Mathematics. Springer, Cham, 2014. Randomness in lattice point counting
work page 2014
-
[4]
Dedekind cotangent sums.Acta Arith., 109(2):109–130, 2003
Matthias Beck. Dedekind cotangent sums.Acta Arith., 109(2):109–130, 2003
work page 2003
-
[5]
Bernoulli-Dedekind sums.Acta Arith., 149(1):65–82, 2011
Matthias Beck and Anastasia Chavez. Bernoulli-Dedekind sums.Acta Arith., 149(1):65–82, 2011
work page 2011
-
[6]
Bruce C. Berndt and Boon P. Yeap. Explicit evaluations and reciprocity theorems for finite trigonometric sums.Adv. in Appl. Math., 29(3):358–385, 2002
work page 2002
-
[7]
Berndt and Alexandru Zaharescu
Bruce C. Berndt and Alexandru Zaharescu. Finite trigonometric sums and class numbers.Math. Ann., 330(3):551–575, 2004
work page 2004
-
[8]
Minimizing point configura- tions for tensor product energies on the torus.arXiv:2510.25442, 2025
Dmitriy Bilyk, Nicolas Nagel, and Ian Ruohoniemi. Minimizing point configura- tions for tensor product energies on the torus.arXiv:2510.25442, 2025
-
[9]
Dmitriy Bilyk, Vladimir N. Temlyakov, and Rui Yu. Fibonacci sets and sym- metrization in discrepancy theory.J. Complexity, 28(1):18–36, 2012
work page 2012
-
[10]
On the theorem of Davenport and generalized Dedekind sums.J
Bence Borda. On the theorem of Davenport and generalized Dedekind sums.J. Number Theory, 172:1–20, 2017
work page 2017
-
[11]
Random walks and quadratic number fields.arXiv:2512.03884, 2025
Bence Borda. Random walks and quadratic number fields.arXiv:2512.03884, 2025. 29
-
[12]
Sergiy V. Borodachov, Douglas P. Hardin, and Edward B. Saff.Discrete energy on rectifiable sets. Springer Monographs in Mathematics. Springer, New York, 2019
work page 2019
-
[13]
Duncan A. Buell.Binary quadratic forms. Springer-Verlag, New York, 1989. Classical theory and modern computations
work page 1989
-
[14]
Elif C ¸ etin. Identities for a special finite sum related to the Dedekind sums and Fibonacci numbers.Gazi University Journal of Science Part A: Engineering and Innovation, 10(2):232–240, 2023
work page 2023
-
[15]
Nancy Childress.Class field theory. Universitext. Springer, New York, 2009
work page 2009
-
[16]
Henri Cohen.A course in computational algebraic number theory, volume 138 of Graduate Texts in Mathematics. Springer-Verlag, Berlin, 1993
work page 1993
-
[17]
Universally optimal distribution of points on spheres.J
Henry Cohn and Abhinav Kumar. Universally optimal distribution of points on spheres.J. Amer. Math. Soc., 20(1):99–148, 2007
work page 2007
-
[18]
Ian G. Connell. Some properties of Beatty sequences. I.Canad. Math. Bull., 2:190–197, 1959
work page 1959
-
[19]
Cox.Primes of the formx 2 +ny 2
David A. Cox.Primes of the formx 2 +ny 2. A Wiley-Interscience Publication. John Wiley & Sons, Inc., New York, 1989. Fermat, class field theory and complex multiplication
work page 1989
-
[20]
Values of the derivatives of the cotangent at rational multiples ofπ.Appl
Djurdje Cvijovi´ c. Values of the derivatives of the cotangent at rational multiples ofπ.Appl. Math. Lett., 22(2):217–220, 2009
work page 2009
-
[21]
New formulae for the Bernoulli and Euler polynomials at rational arguments.Proc
Djurdje Cvijovi´ c and Jacek Klinowski. New formulae for the Bernoulli and Euler polynomials at rational arguments.Proc. Amer. Math. Soc., 123(5):1527–1535, 1995
work page 1995
-
[22]
Advanced Courses in Mathematics
Dinh D˜ ung, Vladimir Temlyakov, and Tino Ullrich.Hyperbolic cross approxima- tion. Advanced Courses in Mathematics. CRM Barcelona. Birkh¨ auser/Springer, Cham, 2018. Edited and with a foreword by Sergey Tikhonov
work page 2018
-
[23]
Josef Dick. Explicit constructions of quasi-Monte Carlo rules for the numeri- cal integration of high-dimensional periodic functions.SIAM J. Numer. Anal., 45(5):2141–2176, 2007
work page 2007
-
[24]
Beziehungen zwischen Dedekindschen Summen.Abh
Ulrich Dieter. Beziehungen zwischen Dedekindschen Summen.Abh. Math. Sem. Univ. Hamburg, 21:109–125, 1957
work page 1957
-
[25]
Cotangent sums, a further generalization of Dedekind sums.J
Ulrich Dieter. Cotangent sums, a further generalization of Dedekind sums.J. Number Theory, 18(3):289–305, 1984
work page 1984
-
[26]
Reciprocity theorems for Dedekind sums
Ulrich Dieter. Reciprocity theorems for Dedekind sums. InIX. Mathematik- ertreffen Zagreb-Graz (Motovun, 1995), volume 328 ofGrazer Math. Ber., pages 11–24. Karl-Franzens-Univ. Graz, Graz, 1996
work page 1995
-
[27]
Karl Dilcher and Jeffrey L. Meyer. Dedekind sums and some generalized Fi- bonacci and Lucas sequences.Fibonacci Quart., 48(3):260–264, 2010
work page 2010
-
[28]
Tichy.Sequences, discrepancies and applications, volume 1651 ofLecture Notes in Mathematics
Michael Drmota and Robert F. Tichy.Sequences, discrepancies and applications, volume 1651 ofLecture Notes in Mathematics. Springer-Verlag, Berlin, 1997
work page 1997
-
[29]
Daniel Duverney, Carsten Elsner, Masanobu Kaneko, and Yohei Tachiya. A crite- rion of algebraic independence of values of modular functions and an application to infinite products involving Fibonacci and Lucas numbers.Res. Number The- ory, 8(2):Paper No. 31, 13, 2022
work page 2022
-
[30]
Richard R. Hall, Julia C. Wilson, and Don Zagier. Reciprocity formulae for general Dedekind-Rademacher sums.Acta Arith., 73(4):389–396, 1995
work page 1995
-
[31]
Douglas P. Hardin and Edward B. Saff. Discretizing manifolds via minimum energy points.Notices Amer. Math. Soc., 51(10):1186–1194, 2004
work page 2004
-
[32]
Extreme and periodicL 2 discrepancy of plane point sets.Acta Arith., 199(2):163–198, 2021
Aicke Hinrichs, Ralph Kritzinger, and Friedrich Pillichshammer. Extreme and periodicL 2 discrepancy of plane point sets.Acta Arith., 199(2):163–198, 2021. 30
work page 2021
-
[33]
Aicke Hinrichs and Jens Oettershagen. Optimal point sets for quasi-Monte Carlo integration of bivariate periodic functions with bounded mixed derivatives. In Monte Carlo and quasi-Monte Carlo methods, volume 163 ofSpringer Proc. Math. Stat., pages 385–405. Springer, [Cham], 2016
work page 2016
-
[34]
Stolarsky interspersions.Ars Combin., 39:129–138, 1995
Clark Kimberling. Stolarsky interspersions.Ars Combin., 39:129–138, 1995
work page 1995
-
[35]
Clark Kimberling. The equationm 2 −4k= 5n 2 and unique representations of positive integers.Fibonacci Quart., 45(4):304–312, 2007
work page 2007
-
[36]
Lucas representations of positive integers.J
Clark Kimberling. Lucas representations of positive integers.J. Integer Seq., 23(9):Art. 20.9.5, 15, 2020
work page 2020
-
[37]
Some identities related to Dedekind sums and the second-order linear recurrence polynomials.Adv
Jianghua Li and Han Zhang. Some identities related to Dedekind sums and the second-order linear recurrence polynomials.Adv. Difference Equ., pages 2013:299, 5, 2013
work page 2013
-
[38]
An elliptic analogue of generalized Dedekind-Rademacher sums.J
Tomoya Machide. An elliptic analogue of generalized Dedekind-Rademacher sums.J. Number Theory, 128(4):1060–1073, 2008
work page 2008
-
[39]
Daniel A. Marcus.Number fields. Universitext. Springer, Cham, second edition,
-
[40]
With a foreword by Barry Mazur
-
[41]
Jiˇ r´ ı Matouˇ sek.Geometric discrepancy, volume 18 ofAlgorithms and Combina- torics. Springer-Verlag, Berlin, 2010. An illustrated guide, Revised paperback reprint of the 1999 original
work page 2010
-
[42]
On certain sums generating the Dedekind sums and their reci- procity laws.Pacific J
Mikl´ os Mikol´ as. On certain sums generating the Dedekind sums and their reci- procity laws.Pacific J. Math., 7:1167–1178, 1957
work page 1957
-
[43]
Hugh L. Montgomery.Ten lectures on the interface between analytic number theory and harmonic analysis, volume 84 ofCBMS Regional Conference Series in Mathematics. Conference Board of the Mathematical Sciences, Washington, DC; by the American Mathematical Society, Providence, RI, 1994
work page 1994
- [44]
-
[45]
On theL 2-discrepancy of Latin hypercubes.Monatsh
Nicolas Nagel. On theL 2-discrepancy of Latin hypercubes.Monatsh. Math., 207(2):309–336, 2025
work page 2025
-
[46]
PhD thesis, Chemnitz University of Technology, 2026
Nicolas Nagel.Discrepancy, Quasi-Monte Carlo and Energy: Optimal Point Sets in the Cube and Torus. PhD thesis, Chemnitz University of Technology, 2026
work page 2026
-
[47]
Nicolas Nagel. Global optimality of 3- and 5-point Fibonacci lattices for quasi- Monte Carlo integration and general energies.J. Complexity, 93:Paper No. 102012, 15, 2026
work page 2026
-
[48]
Springer Monographs in Mathematics
W ladys law Narkiewicz.Elementary and analytic theory of algebraic numbers. Springer Monographs in Mathematics. Springer-Verlag, Berlin, third edition, 2004
work page 2004
-
[49]
J¨ urgen Neukirch.Algebraic number theory, volume 322 ofGrundlehren der math- ematischen Wissenschaften [Fundamental Principles of Mathematical Sciences]. Springer-Verlag, Berlin, 1999. Translated from the 1992 German original and with a note by Norbert Schappacher, With a foreword by G. Harder
work page 1999
-
[50]
Quasi-Monte Carlo methods and pseudo-random numbers
Harald Niederreiter. Quasi-Monte Carlo methods and pseudo-random numbers. Bull. Amer. Math. Soc., 84(6):957–1041, 1978
work page 1978
-
[51]
Society for Industrial and Applied Mathematics (SIAM), Philadelphia, PA, 1992
Harald Niederreiter.Random number generation and quasi-Monte Carlo methods, volume 63 ofCBMS-NSF Regional Conference Series in Applied Mathematics. Society for Industrial and Applied Mathematics (SIAM), Philadelphia, PA, 1992
work page 1992
-
[52]
Volume II: Standard information for functionals, volume 12 ofEMS Tracts in Mathematics
Erich Novak and Henryk Wo´ zniakowski.Tractability of multivariate problems. Volume II: Standard information for functionals, volume 12 ofEMS Tracts in Mathematics. European Mathematical Society (EMS), Z¨ urich, 2010. 31
work page 2010
-
[53]
16 ofThe Carus Mathematical Monographs
Hans Rademacher and Emil Grosswald.Dedekind sums, volume No. 16 ofThe Carus Mathematical Monographs. Mathematical Association of America, Wash- ington, DC, 1972
work page 1972
-
[54]
Chance Sanford. A remark on Dedekind sums and palindromic continued frac- tions.Fibonacci Quart., 61(4):357–360, 2023
work page 2023
-
[55]
On generalized Dedekind sums.J
Lajos Tak´ acs. On generalized Dedekind sums.J. Number Theory, 11(2):264–272, 1979
work page 1979
-
[56]
Joseph J. Thomson. XXIV. On the structure of the atom: an investigation of the stability and periods of oscillation of a number of corpuscles arranged at equal intervals around the circumference of a circle; with application of the results to the theory of atomic structure.The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 7(...
work page 1904
-
[57]
Washington.Introduction to cyclotomic fields, volume 83 ofGrad- uate Texts in Mathematics
Lawrence C. Washington.Introduction to cyclotomic fields, volume 83 ofGrad- uate Texts in Mathematics. Springer-Verlag, New York, second edition, 1997
work page 1997
-
[58]
Zagier.Zetafunktionen und quadratische K¨ orper
Don B. Zagier.Zetafunktionen und quadratische K¨ orper. Hochschultext. [Uni- versity Textbooks]. Springer-Verlag, Berlin-New York, 1981. Eine Einf¨ uhrung in die h¨ ohere Zahlentheorie. [An introduction to higher number theory]
work page 1981
-
[59]
On the Fibonacci numbers and the Dedekind sums.Fibonacci Quart., 38(3):223–226, 2000
Wenpeng Zhang and Yuan Yi. On the Fibonacci numbers and the Dedekind sums.Fibonacci Quart., 38(3):223–226, 2000
work page 2000
-
[60]
Feng-Zhen Zhao and Tianming Wang. Some results on generalized Fibonacci and Lucas numbers and Dedekind sums.Fibonacci Quart., 42(3):250–255, 2004. Appendix A. Auxiliary results A.1.Floor function Here we collect some results concerning the floor function that are used throughout Section 2. Similar relations have been proven and used for example in [18, 34...
work page 2004
-
[61]
(ii):Ifx=y, both sides are 0 and the inequality is obviously true
The statement now follows by taking the inverses. (ii):Ifx=y, both sides are 0 and the inequality is obviously true. Therefore, without loss of generality letx < yand consider the ratio R(x, y) := 1 sin(πx)σ − 1 sin(πy) σ 1 x + 1 y σ−1 1 x − 1 y = xσyσ|sin(πy) σ −sin(πx) σ| sin(πx)σ sin(πy) σ(x+y) σ−1|y−x| . By (i),x σ sin(πx)−σ ≤1, respectively fory. Fur...
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.