Pith. Sign in

REVIEW

Certified Collision Exclusion and an Unconditional Upper Bound $\Lambda<0.156821$ for the de Bruijn--Newman Constant

Number Theory · Submitted 4 Nov 2026 · 21 references

Pith's verdict: Ambitious but fragile: the collision-exclusion method is new and the bound improves the record, but the proof's narrow feasibility margin and extreme complexity mean it needs careful independent validation.

T0 · AI review

How this review was made: An AI referee (deepseek/deepseek-v4-flash) read the paper on November 5, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

  1. T0 AI review An AI read the paper and answered a fixed list of questions.
  2. T1 Audit Automatic checks that the references and files the paper relies on exist and match.
  3. T2 Compute The paper's code or calculations re-run with the same results.
  4. T3 Formal statement The claims written out in a formal math language a computer can read.
  5. T4 Proof Those claims proved, and the proof checked by computer.

How Pith checks papers →

· 3 major objections · 7 minor · Ask about this paper · The compiled record · Read the full review →
Challenge this review Comment (0) Read on arXiv ↗
Cite ▾
arXiv ID2611.06245 (version 1)
Pith IDYREDTE7G, Pith's permanent record of this paper and its review
CitationDale James Raymond, Michel Planat. "Certified Collision Exclusion and an Unconditional Upper Bound $\Lambda<0.156821$ for the de Bruijn--Newman Constant." arXiv:2611.06245 (2026). https://pith.science/paper/YREDTE7G
Cite this reviewBibTeX for Pith's review of this paper
Claim paper

Why Pith says this

Highlight any text to comment on it.

Referee report
The paper

The paper claims

An unconditional upper bound Λ < 0.156821 for the de Bruijn–Newman constant is proved via a certified collision-exclusion method that replaces the canopy criterion with a real double-zero exclusion.

The reading

The paper proves that the de Bruijn–Newman constant Λ, the critical heat time beyond which all zeros of the deformed Riemann ξ-function become real, satisfies Λ < 0.156821. This improves the best previously published unconditional bound of 0.2 (Platt–Trudgian 2021) by a substantial margin, using only the same finite Riemann hypothesis verification up to height 3 trillion. The central innovation is a global collision-exclusion theorem that prevents multiple real zeros from appearing on a closed interval of heat times, rather than relying on a complex zero-free canopy as in earlier work. The proof combines five certified prime-polynomial source polynomials, a balanced real-jet transfer, a uniform Euler-product barrier at infinity, and a compact-interior propagation theorem, all assembled into a closed time-band exclusion that forces strictness at the proposed endpoint. The entire finite certificate is publicly archived and auditable through 664,505 structural Fourier coefficients, 44,182 torus boxes, and 17,385 separator rectangles.

What carries the argument

The central mechanism is the collision-exclusion framework: replacing the canopy criterion (which prohibits nonreal zeros crossing a complex boundary) with the global exclusion of real double zeros (H_t, H'_t) = (0,0) on a closed time interval. This is reduced, after a balanced real gauge, to a positivity statement for a Hermitian form in a pair of analytic prime-polynomial coordinates. The five stable Gram source polynomials (MA1) – each defined on a specific index interval with a synthetic fibre δ_j and weight ϑ_j – satisfy a strict torus inequality (G) that ensures, via Lemma 4.3 (ordinary weighted recovery), that the full source polynomial never vanishes on the closed unit polydisc and has modulus > δ_j. The balanced real-jet transfer (Theorem 3.1 and Corollary 3.2) converts this polynomial lower bound into a nonvanishing lower bound for the physical pair (H_t, H'_t) over the finite exterior. For the infinite exterior, a uniform Euler-product barrier (Section 8) yields a positive lower bound for u² + u_x² through a differential inequality on the completed resultant matrix. The stationary separator (Section 6) and compact interior theorem (Theorem 7.2) handle the remaining regions.

Extended reading notes

Core claim

The paper establishes that Λ < 156821/1000000 = 0.156821, and does so by excluding the possibility of a multiple real zero at any point in the time band [0.156821, 0.2] and spatial region |x| ≥ 6000000185827 ∪ [X,W] ∪ [W,∞) (with explicit constants). The argument separates three regions: a stationary separator at x = X, a compact interior where all zeros are real and simple by propagation, a finite exterior where five Gram sources guarantee a stable polynomial modulus > 1/790, and an infinite exterior where a differential inequality gives u² + u_x² > 3/10000. A critical-time compactness lemma shows that if Λ lies in the band, H_Λ would have a finite multiple real zero; the regional exclusions contradict that, forcing Λ below the band. The proof does not assume any new zero-free half-plane or unverified analytic hypotheses beyond the published Polymath approximations and Platt–Trudgian finite-RH result.

Load-bearing premise

The five prime-polynomial Gram sources (MA1) must satisfy the strict positivity conditions of the torus inequality (G) and the ordinary weighted recovery inequality (OR1) with exact, outward-rounded rational coefficients; if any single source certificate is invalid due to rounding, a missed term, or a narrow feasibility margin, the finite-exterior exclusion could fail and the bound might not hold.

Editorial extensions

If this is right

  • The unconditional upper bound for Λ is lowered from 0.2 to 0.156821, providing the sharpest published unconditional bound in the Polymath normalisation.
  • The collision-exclusion method offers a new global framework for bounding Λ that, unlike the canopy approach, does not require a nonzero imaginary part of the zero-free region, and thus may be more amenable to further refinement with stronger finite-RH data.
  • The proof demonstrates that the Platt–Trudgian verification up to 3 trillion is sufficient to support a substantially better bound than the previously published 0.2, showing the power of the method over a simple barrier estimate.
  • The public certificate archive (with 44,182 torus boxes, 17,385 separator rectangles, etc.) sets a high standard for reproducibility; an independent re-execution would either confirm the bound or reveal a flaw, making the result auditable.
  • If the bound is accepted, the gap between the best conditional bounds (≈0.107965 under H₇/₈) and the best unconditional bound is narrowed, highlighting the remaining distance to Λ=0 needed for the Riemann hypothesis.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The narrow feasibility margin (≈5.8×10⁻⁷ below the endpoint) observed for the four-prime Gram family suggests that any further improvement with the same polynomial architecture may require either a different weight distribution or the inclusion of a fifth prime in the smooth fibre, as the authors acknowledge.
  • The collision-exclusion method separates the global problem into independent regional certificates; therefore, future improvements in the finite-RH height or in the source polynomial construction can be plugged in directly without re-proving the entire assembly, making incremental progress on Λ a modular task.
  • The explicit certification of the four-prime Cauchy–Schwarz obstruction (Proposition 4.1) gives a precise feasibility ceiling for that family, which could guide the search for alternative polynomial bases that avoid the obstruction and potentially push the bound toward 0.15 or lower.
  • The paper's careful distinction between unconditional and conditional/unrefereed bounds (Table 1) clarifies the logical status of several recent claims, which may influence how the community evaluates progress on the de Bruijn–Newman constant.
Original abstract

The de Bruijn--Newman constant $\Lambda$ is the transition time beyond which all zeros of the heat-deformed Riemann $\xi$-function are real. We develop a computer-assisted collision-exclusion method and obtain the bound $\Lambda<156821/10^6=0.156821$, in the normalisation of Polymath. The proof combines the published finite-height verification and the starting inequality $\Lambda\leq1/5$ with a compact-interior continuation theorem, five stable prime-polynomial Gram sources, certified moving-index recovery, a balanced real-jet transfer and a uniform Euler-product barrier at infinity. The resulting closed time-band exclusion, together with uniform remote reality, forces strictness at the proposed endpoint. The finite certificate uses 664,505 structural Fourier coefficients, 44,182 closed torus boxes, 184 separator moments and 17,385 separator rectangles. We isolate a Cauchy--Schwarz obstruction intrinsic to the four-prime source family, explaining the narrow feasibility margin of the certified endpoint. We state the proof-to-certificate interface and distinguish the present unconditional logical claim from other recent, as yet unrefereed, computational bounds.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-11-05: 1 request, 5,781 input tokens.

What the abstract itself states, as probabilities: claims first 0.06 · states limitation 0.81 · human participants 0.02 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.79 · mentions code or data availability 0.05.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

The de Bruijn--Newman constant $\Lambda$ is the transition time beyond which all zeros of the heat-deformed Riemann $\xi$-function are real. We develop a computer-assisted collision-exclusion method and obtain the bound $\Lambda<156821/10^6=0.156821$, in the normalisation of Polymath. The proof combines the published finite-height verification and the starting inequality $\Lambda\leq1/5$ with a compact-interior continuation theorem, five stable prime-polynomial Gram sources, certified moving-index recovery, a balanced real-jet transfer and a uniform Euler-product barrier at infinity. The resulting closed time-band exclusion, together with uniform remote reality, forces strictness at the proposed endpoint. The finite certificate uses 664,505 structural Fourier coefficients, 44,182 closed torus boxes, 184 separator moments and 17,385 separator rectangles. We isolate a Cauchy--Schwarz obstruction intrinsic to the four-prime source family, explaining the narrow feasibility margin of the certified endpoint. We state the proof-to-certificate interface and distinguish the present unconditional logical claim from other recent, as yet unrefereed, computational bounds.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 The de Bruijn--Newman constant $\Lambda$ is the transition time beyond which all zeros of the heat-deformed Riemann $\xi$-function are real. background 1.00 0.04 0.03 asserted 1.00
s1 We develop a computer-assisted collision-exclusion method and obtain the bound $\Lambda<156821/10^6=0.156821$, in the normalisation of Polymath. result 0.90 0.97 0.93 asserted 1.00
s2 The proof combines the published finite-height verification and the starting inequality $\Lambda\leq1/5$ with a compact-interior continuation theorem, five stable prime-polynomial Gram sources, certified moving-index recovery, a balanced real-jet transfer and a uniform Euler-product barrier at infinity. method 0.97 0.79 0.32 asserted 1.00
s3 The resulting closed time-band exclusion, together with uniform remote reality, forces strictness at the proposed endpoint. interpretation 0.90 0.64 0.08 asserted 0.98
s4 The finite certificate uses 664,505 structural Fourier coefficients, 44,182 closed torus boxes, 184 separator moments and 17,385 separator rectangles. method 0.93 0.84 0.02 asserted 1.00
s5 We isolate a Cauchy--Schwarz obstruction intrinsic to the four-prime source family, explaining the narrow feasibility margin of the certified endpoint. interpretation 0.46 0.91 0.03 asserted 1.00
s6 We state the proof-to-certificate interface and distinguish the present unconditional logical claim from other recent, as yet unrefereed, computational bounds. contribution 0.73 0.86 0.04 asserted 0.89

What kind of paper the classifier reports this is: theoretical result 0.99 · evidence from proof or derivation 0.51.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

References

Discussion

Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.