REVIEW 2 major objections 4 minor 34 references
On the Effective Non-vanishing of Hecke--Maass $L$-functions at Special Points
T0 review · 2 major / 4 minor · reviewed 2026-08-06 · deepseek-v4-flash
Pith's one-line read The paper proves that at least one third of the special Hecke--Maass $L$-values $L(\tfrac12+it_f,f)$ with $t_f\le T$ are non-zero, with the proportion rising to one half under the Riemann hypothesis.
desk verdict A real result: first effective 33% non-vanishing for special Hecke–Maass L-values, with the main soft spot being the deferred Bessel lemmas that deserve a careful referee check. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The argument is carried by two kinds of spectral averages. First, the twisted first and second moments $C_\delta^1(m)$ and $C_\delta^2(m_1,m_2)$ over the even or odd Maass spectrum, weighted by the harmonic weight $\omega_f$ and a Gaussian in $t_f$. The Kuznetsov trace formula splits these averages into diagonal, Eisenstein, and off-diagonal terms; the off-diagonal terms are sums of Kloosterman sums against Bessel transforms, and the Bessel analysis in Section 4 (with full proofs deferred to the companion paper [Qi]) gives the asymptotics of those transforms, while Poisson summation and standard bounds for Kloosterman sums control the off-diagonal terms. The resulting asymptotic formulae, Theorems 5 and 6, supply explicit main terms: $C_\delta^1(m)=\Pi T/(\pi\sqrt\pi)\delta(m,1)+\cdots$ and $C_\delta^2(m_1,m_2)$ with main term $(\Pi T/(\pi\sqrt\pi r))\big((\log T/r+\gamma_\delta)\Sigma(\mathbf m)-2\bar\Sigma(\mathbf m)\big)$, where $r=m_1m_2/(m_1,m_2)^2$ and $\Sigma$ is a divisor sum. Second, a mollifier---a short Dirichlet polynomial whose coefficients are optimized by divisor inversion and the Prime Number Theorem---feeds these moments into Cauchy's inequality, producing the one-third lower bound; an unsmoothing lemma converts the smooth weight to sharp intervals. For the Riemann-hypothesis results, the same spectral machinery is applied to the one-level density at the special point through the explicit formula, and an extended density theorem with support $v(\mu)=\min\{3\mu,1+\mu\}$ is proved using variant Kloosterman sums and an identity that splits an ordinary Kloosterman sum into them.
What would settle it
A direct computation for a full spectrum up to large $T$ showing fewer than one third of $L(\tfrac12+it_f,f)$ non-zero would falsify Theorem 1; since that is currently out of reach, the sharpest available check is numerical verification of the Bessel integrals in Lemmas 4.1--4.3, for example the asymptotic (4.7), because the moment asymptotics and hence the one-third bound rest on them.
Extended reading notes
Core claim
On the paper's own terms, the central discovery is that the special values $L(s_f,f)$ with $s_f=\tfrac12+it_f$ are non-vanishing for an explicit positive proportion of the spectrum, with the same constant on both parities: for $\delta=0,1$ and for the full basis $\mathcal B$, the liminf over $T$ of the proportion of $f$ with $t_f\le T$ and $L(s_f,f)\ne0$ is at least $1/3$. For short intervals the liminf is at least $\min\{1/3,(2\mu+1)/(2\mu+5)\}$, refining an earlier unexplicit result. Assuming the Riemann hypothesis for all $L(s,f)$ and Dirichlet $L$-functions, the long-interval proportion rises to at least $1/2$, and for $1/2<\mu<1$ the short-interval proportion rises to $\mu/(\mu+1)$; for small $\mu$ the conditional method does not beat the unconditional one, a feature the paper highlights. An addendum improves the conditional non-vanishing of central values as well, giving liminf greater than $9/16$ on the even basis and greater than $15/16$ on the odd basis.
Load-bearing premise
The load-bearing premise is that the technical estimates for Bessel-function integrals used in the moment computations are correct: Lemmas 4.1--4.3 are deferred to a companion paper, and the odd-integral extension is stated without full detail, so the one-third proportion stands or falls with that analysis.
Editorial extensions
If this is right
- For each parity $\delta=0,1$ and for the full basis $\mathcal B$, at least one third of the special values $L(\tfrac12+it_f,f)$ with $t_f\le T$ do not vanish as $T\to\infty$.
- On windows $|t_f-T|\le T^\mu$, $0<\mu<1$, the unconditional non-vanishing proportion is at least $\min\{1/3,(2\mu+1)/(2\mu+5)\}$, making the earlier unspecified proportion effective.
- Under the Riemann hypothesis for $L(s,f)$ and Dirichlet $L$-functions, the long-interval proportion is at least $1/2$, and for $1/2<\mu<1$ the short-interval proportion is at least $\mu/(\mu+1)$; for $\mu\le 1/2$ the conditional bound is weaker than the unconditional $1/3$.
- The asymptotic formulae for the twisted first and second moments give the leading-order distribution of $L(\tfrac12+it_f,f)$ at the special point, which can serve as a quantitative baseline for further statistics of these values.
- Because the special values do not vanish trivially on the odd basis, the $1/3$ lower bound applies equally to both parity classes, unlike central values.
Reading between the lines
- The one-third constant is a lower bound supplied by the method, not a prediction of the true proportion; the conditional jump to one half suggests that improving the unconditional off-diagonal and Bessel control is the natural route to larger constants.
- The same moment machinery, with the deferred Bessel estimates in place, could plausibly be applied to other families evaluated at their spectral points, such as Rankin--Selberg values connected to cusp-form deformation questions, to replace unspecified proportions with explicit ones.
- A numerical check on moderately large $T$ comparing the computed non-vanishing ratio of $L(\tfrac12+it_f,f)$ with $1/3$, $1/2$, and the short-interval constants would be a testable extension, and a ratio systematically above $1/3$ would support the view that the true proportion is larger.
- The saturation of the unconditional bound for $\mu\le 1/2$ indicates that on very short intervals the bottleneck is the diagonal--mollifier balance rather than the zero-density range, so subconvexity or refined mollifier choices may be the right extension target.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proves nonvanishing results for Hecke-Maass L-functions at the special point s_f = 1/2 + it_f. The main unconditional theorem (Theorem 1) states that for each parity class B_delta, at least one third of the values L(s_f, f) with t_f <= T are nonzero as T grows, and the same holds on the full basis B. Theorem 2 gives a short-interval version with proportion min{1/3, (2mu+1)/(2mu+5)}. Under the Riemann hypothesis for the relevant L-functions and Dirichlet L-functions, Theorems 3 and 4 raise the long-interval proportion to 1/2 and give mu/(mu+1) for mu > 1/2. The proof combines the Kuznetsov formula, approximate functional equations, Bessel-integral analysis, a mollifier method, and an extended density theorem for the 1-level density of L(s_f, f). The paper is technically dense and the main line of argument is plausible, but several load-bearing estimates are deferred or misstated and need correction.
Significance. If the central claims are correct, this is a substantial advance: it gives the first explicit nonvanishing proportion above the 25% known for central values, does so separately in the even and odd families, and includes effective short-interval refinements. The method is a careful combination of standard tools, and the paper is unusually explicit about the constants and error terms. The density-theorem part identifies the unitary symmetry of the family and is of independent interest. The main caveat is that the unconditional 33% result depends on Bessel-integral estimates whose H^- variant is deferred to a companion paper; this is a genuine load-bearing point. The paper does not provide machine-checked proofs or code, but the analytic structure is transparent enough that verification is feasible.
major comments (2)
- [Section 4, Lemmas 4.1-4.3 and Corollary 4.1] The H^- extension of the Bessel-integral analysis is asserted to follow "by literally the same proofs" from the companion paper [Qi], but the phase in Lemma 4.2 is f_-(r;v,w)=v e^r - w e^{-r}, obtained through the I-Bessel identity (2.8), and the stationary-phase analysis is not literally identical to the H^+ case. Since Corollary 4.1 supplies the c-truncation used in Lemmas 8.2 and 9.3, and hence the error term in Theorem 6, the 1/3 nonvanishing constant depends directly on this deferred analysis. The paper should either include the H^- proofs or give a precise statement of the modifications needed and confirm that the companion paper contains them.
- [Section 9.2, Lemma 9.2, and Theorem 6] The error term in Lemma 9.2 and Theorem 6 is stated as O(T^epsilon( Pi sqrt(T) + T sqrt(r) + Pi^3/(T sqrt(r)) )), but the derivation leading to (9.12) yields an error of order T^{1+epsilon}/sqrt(r) from the diagonal/off-diagonal split, together with Pi T^{1/2+epsilon} and Pi^3 T^epsilon/(T sqrt(r)). With the printed T sqrt(r), the contribution to the mollified second moment in Section 10.3 would be of size T times a sum of 1/gcd(m1,m2), which is about T M^2; this is incompatible with the constraints in Lemma 10.2 and would block the nonvanishing proportion. The text in Section 10.3 appears to use the correct T/sqrt(r) form, so the statements in Lemma 9.2 and Theorem 6 should be corrected and all later uses checked.
minor comments (4)
- [Section 10.4, equations (10.23) and (10.24)] The displayed optimization uses "max" where the argument and the final statements (10.28) and Theorem 2 use "min". The printed max would claim a proportion exceeding 1/3 in the range mu > 1/2, which is not what the method proves.
- [Section 15.2, last sentence] The phrase "Lemma (15.1)" should read "Lemma 15.1".
- [Section 10.4, removal of the harmonic weight] The passage from the weighted lower bound to the unweighted statements in Theorems 1 and 2 is delegated to the Kowalski-Michel method and a citation to [BHS]. Since Theorem 1 is an unweighted density statement, it would be helpful to spell out the specific lemma or adaptation being used.
- [Section 4, Remark 4.1] The even case requires a split treatment with two different choices of Re(v) and regularity parameters. This is plausible, but a short explanation of why the two regimes overlap and cover all relevant u would improve readability.
Circularity Check
No circularity: the 1/3 non-vanishing bound follows from independently computed twisted moments and an optimized mollifier; deferred Bessel lemmas are a completeness gap, not a circular step.
full rationale
The proof of Theorem 1 is a standard mollifier-moment argument: the first and second twisted moments are evaluated by the Kuznetsov trace formula and approximate functional equations (Theorems 5 and 6), and the mollifier coefficients are chosen by Cauchy's inequality to maximize the ratio M1^2/M2. No parameter is fitted to the non-vanishing statistic, and no equation defining the target quantity is reused as a conclusion. The self-citations to [Qi], [LQ1], and [LQ2] supply auxiliary analytic facts (Bessel transforms, weighted Weyl law, unsmoothing) whose assumptions are stated in terms of test functions and spectral parameters, not in terms of the non-vanishing proportion being proved. In particular, Corollary 4.1 depends on Lemmas 4.1-4.3 whose proofs are deferred to the companion paper [Qi]; this is a completeness/deferral risk, not a circular reduction, because the companion results are independent Bessel-integral estimates and do not presuppose the 33% conclusion. The 'max' in (10.23) is a typographical slip corrected by 'min' in Theorem 2 and (10.28). No circularity score above 0 is warranted.
Assumptions & free parameters
assumptions (4)
- standard math Kuznetsov trace formula for even and odd Maass cusp forms on SL_2(Z), equation (2.9), is valid.
- standard math Kim-Sarnak bound |α_f(p)|, |β_f(p)| ≤ p^{7/64} in equation (3.7) holds for all primes p.
- ad hoc to paper The Bessel integral estimates in Lemmas 4.1-4.3, including the H^- case, are valid as stated, with proofs deferred to the companion paper [Qi, arXiv:2506.08546].
- domain assumption The Riemann hypothesis for Dirichlet L-functions and for the family L(s,f) holds, for Theorems 3, 4, 9, and 10.
Cite this review
Pith. "Pith review of On the Effective Non-vanishing of Hecke--Maass $L$-functions at Special Points." pith.science (2026). https://pith.science/paper/EWTYYNT2
@misc{pith2026250714566,
author = {Pith},
title = {Pith review of: On the Effective Non-vanishing of Hecke--Maass $L$-functions at Special Points},
year = {2026},
howpublished = {\url{https://pith.science/paper/EWTYYNT2}},
note = {Machine review of arXiv:2507.14566}
}
abstract
In this paper, we consider the non-vanishing problem for the family of special Hecke--Maass $L$-values $ L (1/2+it_f, f) $ with $f (z)$ in an orthonormal basis of (even or odd) Hecke--Maass cusp forms of Laplace eigenvalue $1/4 + t_f^2$ ($t_f > 0$). We prove that 33% of $L (1/2+it_f, f)$ for $ t_f \leqslant T$ do not vanish as $T \rightarrow \infty$. For comparison, it is known that the non-vanishing proportion is at least 25% for the central $L$-values $L (1/2, f)$. Further, 33% may be raised to 50% conditionally on the generalized Riemann hypothesis. Moreover, we prove non-vanishing results on short intervals $|t_f-T| \leqslant T^{\mu}$ for any $0 < \mu < 1$. However, it is a curious case that the Riemann hypothesis does not yield better result for small $0 < \mu \leqslant 1/2$.
Reference graph
Works this paper leans on
-
[1]
L. Alpoge and S. J. Miller. Low-lying zeros of M aass form L -functions. Int. Math. Res. Not. IMRN , (10):2678--2701, 2015
work page 2015
-
[2]
O. Balkanova, B. Huang, and A. S\" o dergren. Non-vanishing of M aass form L -functions at the central point. Proc. Amer. Math. Soc. , 149(2):509--523, 2021
work page 2021
-
[3]
H. Bohr and E. Landau. Sur les z\'eros de la fonction (s) de R iemann. C. R. Acad. Sci. Paris , 158:106--110, 1914
work page 1914
-
[4]
V. Blomer. Subconvexity for twisted L -functions on GL (3) . Amer. J. Math. , 134(5):1385--1421, 2012
work page 2012
- [5]
-
[6]
J. Bourgain and N. Watt. Decoupling for perturbed cones and the mean square of | ( 12+it)| . Int. Math. Res. Not. IMRN , (17):5219--5296, 2018
work page 2018
-
[7]
J. B. Conrey and H. Iwaniec. The cubic moment of central values of automorphic L -functions. Ann. of Math. (2) , 151(3):1175--1216, 2000
2000
-
[8]
J.-M. Deshouillers and H. Iwaniec. The nonvanishing of R ankin- S elberg zeta-functions at special points. The S elberg T race F ormula and R elated T opics ( B runswick, M aine, 1984) , Contemp. Math., Vol. 53 , 51--95. Amer. Math. Soc., Providence, RI, 1986
work page 1984
Show all 34 references
-
[9]
Ivi\' c and M
A. Ivi\' c and M. Jutila. On the moments of H ecke series at central points. II . Funct. Approx. Comment. Math. , 31:93--108, 2003
2003
-
[10]
Iwaniec and E
H. Iwaniec and E. Kowalski. Analytic N umber T heory , American Mathematical Society Colloquium Publications, Vol. 53 . American Mathematical Society, Providence, RI, 2004
2004
-
[11]
Iwaniec and X
H. Iwaniec and X. Li. The orthogonality of H ecke eigenvalues. Compos. Math. , 143(3):541--565, 2007
2007
-
[12]
Iwaniec, W
H. Iwaniec, W. Luo, and P. Sarnak. Low lying zeros of families of L -functions. Inst. Hautes \'Etudes Sci. Publ. Math. , (91):55--131 (2001), 2000
2001
-
[13]
Iwaniec and P
H. Iwaniec and P. Sarnak. The non-vanishing of central values of automorphic L -functions and L andau- S iegel zeros. Israel J. Math. , 120(part A):155--177, 2000
2000
-
[14]
H. H. Kim. Functoriality for the exterior square of GL _4 and the symmetric fourth of GL _2 . J. Amer. Math. Soc. , 16(1):139--183, 2003. With appendix 1 by Dinakar Ramakrishnan and appendix 2 by Kim and Peter Sarnak
2003
-
[15]
Kowalski and P
E. Kowalski and P. Michel. The analytic rank of J_0(q) and zeros of automorphic L -functions. Duke Math. J. , 100(3):503--542, 1999
1999
-
[16]
Kowalski and P
E. Kowalski and P. Michel. A lower bound for the rank of J_0(q) . Acta Arith. , 94(4):303--343, 2000
2000
-
[17]
N. M. Katz and P. Sarnak. Random M atrices, F robenius E igenvalues, and M onodromy , American Mathematical Society Colloquium Publications . Vol. 45. American Mathematical Society, Providence, RI, 1999
1999
-
[18]
X. Li. Bounds for GL (3) GL (2) L -functions and GL (3) L -functions. Ann. of Math. (2) , 173 (1):301--336, 2011
2011
-
[19]
X. Li. A weighted W eyl law for the modular surface. Int. J. Number Theory , 7(1):241--248, 2011
2011
-
[20]
S.-C. Liu. and Z. Qi. Low-lying zeros of L -functions for M aass forms over imaginary quadratic fields. Mathematika , 66(3):777--805, 2020
2020
-
[21]
Liu and Z
S.-C. Liu and Z. Qi. Moments of central L -values for M aass forms over imaginary quadratic fields. Trans. Amer. Math. Soc. , 375(5):3381--3410, 2022
2022
-
[22]
W. Luo. On the nonvanishing of R ankin- S elberg L -functions. Duke Math. J. , 69(2):411--425, 1993
1993
-
[23]
W. Luo. The spectral mean value for linear forms in twisted coefficients of cusp forms. Acta Arith. , 70(4):377--391, 1995
1995
-
[24]
W. Luo. Nonvanishing of L -values and the W eyl law. Ann. of Math. (2) , 154(2):477--502, 2001
2001
-
[25]
W. Luo. Refined asymptotics for second spectral moment of R ankin- S elberg L -functions at the special points. Int. Math. Res. Not. IMRN , (23):5457--5483, 2012
2012
-
[26]
Magnus, F
W. Magnus, F. Oberhettinger, and R. P. Soni. Formulas and T heorems for the S pecial F unctions of M athematical P hysics . 3rd enlarged edition. Die Grundlehren der mathematischen Wissenschaften, Band 52. Springer-Verlag New York, Inc., New York, 1966
1966
-
[27]
R. S. Phillips and P. Sarnak. On cusp forms for co-finite subgroups of PSL (2, R ) . Invent. Math. , 80(2):339--364, 1985
1985
-
[28]
Z. Qi. O n the effective non-vanishing of R ankin-- S elberg L -functions at special points. arXiv: 2506.08546 , 2025
2025 arXiv
-
[29]
Rudnick and P
Z. Rudnick and P. Sarnak. Zeros of principal L -functions and random matrix theory. Duke Math. J. , 81(2):269--322, 1996
1996
-
[30]
A. Selberg. On the zeros of R iemann's zeta-function. Collected Papers. V ol. I , Contemp. Math., Vol. 53 , 85--141. Springer-Verlag, Berlin, 1989
1989
-
[31]
E. C. Titchmarsh. The T heory of the R iemann Z eta- F unction . The Clarendon Press, Oxford University Press, New York, 2nd edition, 1986. Edited and with a preface by D. R. Heath-Brown
1986
-
[32]
G. N. Watson. A T reatise on the T heory of B essel F unctions . Cambridge University Press, Cambridge, England; The Macmillan Company, New York, 1944
1944
-
[33]
Z. Xu. Nonvanishing of automorphic L -functions at special points. Acta Arith. , 162(4):309--335, 2014
2014
-
[34]
M. P. Young. Weyl-type hybrid subconvexity bounds for twisted L -functions and H eegner points on shrinking sets. J. Eur. Math. Soc. (JEMS) , 19(5):1545--1576, 2017
2017
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