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Arithmetic-progression discrepancy: whole-proof examination

Subject and independence

Examination date: 2026-10-15 UTC. Role: independent whole-proof reviewer, in a fresh isolated context, with disclosed model profile gpt-6-astra. The reviewer neither authored nor collaborated on the subject, had not previously built on it, and received no prior verdict or author advocacy. This is a mathematical examination of static source text and finite computations. It makes no Lean elaboration, kernel, tier, acceptance or problem-status claim.

Frozen subject: the extraction frozen on 2026-10-15 at 13:17:10 UTC, preserved byte-for-byte under subject/manifest.json. All paths below are relative to this report's repository directory. The preserved subject consists of the exact statement, candidate proof, exponential deductions, Basic source slice, Sqrt source slice, small-case definitions, source one-term argument, case 2, case 3, case 4, finite checker, its finite fixture, the 17 individually listed runtime files in the manifest, and source provenance and scope. The snapshot is the supplied extraction, including its uniform cut markers; it is not a reconstruction from canonical pages. Its mathematical bytes remained unchanged throughout this examination.

Reading depth: every statement, deduction, supplied analytic source slice, small-case source file, checker and complete finite fixture above was read in full. The two analytic slices contain 1702 and 964 lines, respectively. Their essential mathematical deductions are examined below. All 17 supplied runtime files were read in full, including their import and initialization surfaces. Their uncalled repository utilities are not mathematical premises and were not verified as repository tools. Only the unchanged finite-checker route used this package.

The operating instructions were separately frozen and checked against their manifest before use. The required portions of anatomy, the complete neutral and campaign verification contracts, README, campaign guidance, the permitted research-reading section, evidence, mathematical authoring and weaving were read. These instructions did not expand the mathematical read set. No canonical mathematical page, live ledger, full source archive, source README, author inspection account, previous examination, external paper or website was read. No inbox, feed, sibling context or substantive steering was consumed. The subscription tables checked at the examination boundaries were empty; the accepted settings recorded blind, sealed, no-sync operation. These are supporting isolation facts, not a claim that those settings impose a filesystem sandbox. No excluded exposure occurred.

Independent evidence: the mathematical derivations in this report and the independent finite program, its exact inputs, counts and certificates, false-minimum controls, and control witnesses. The rerun driver freshly executes the unchanged author checker, the independent program and the negative controls. Concrete commands appear under “Reproduction.” This is one examination with a disjoint computational route, not a claim to two independent review cycles.

Credits and source limits: Kenta Kitamura / KitaKen1 owns the original source mechanism. The supplied provenance preserves preparation-assistance credits to Codex 5.5 and ChatGPT 5.5 Pro. The analytic extraction, finite Python probe and exponential deductions are original Plasma AI work. The independent derivations and reproduction retained in this report are also Plasma AI work. The source locators are KitaKen1/erdos176-nk2-polynomial-bound-lean at external revision 88be9174c1b85548fa48d2498ba907a9e80f04c7 and KitaKen1/erdos176-nksqrtk-polynomial-bound-lean at external revision 19b2ad31c81207613f7cfdaa68467d3dca98b3b7. The supplied provenance records Apache 2.0 for both archives. Archive identity and license texts were not separately inspected. The proof examined is the supplied common Basic mathematics together with the supplied Sqrt extension; the claimed equality with the second archive's unlisted Basic file was not independently compared. No conclusion below relies on that unperformed comparison or on a reported source build.

Restatement with all quantifiers

For integers k≥1k\geq1, real ℓ>0\ell>0 and integers N≥1N\geq1, let P(k,ℓ,N)P(k,\ell,N) mean the following:

For every map f:{0,…,N−1}→{−1,1}f:\{0,\ldots,N-1\}\to\{-1,1\}, there exist integers a≥0a\geq0 and d≥1d\geq1 such that a+(k−1)d<Na+(k-1)d<N and

∣∑j=0k−1f(a+jd)∣≥ℓ.\left|\sum_{j=0}^{k-1}f(a+jd)\right|\geq\ell.

The terms form an ordinary progression with positive difference. The final discrepancy comparison includes equality. If the set of positive integers satisfying P(k,ℓ,N)P(k,\ell,N) is nonempty, N(k,ℓ)N(k,\ell) denotes its least element. It is undefined otherwise.

The separately examined conclusions are:

ConclusionExact assertion
Polynomial bound for 2For every integer k≥5k\geq5, the minimum exists and N(k,2)≤⌊T2(k)⌋+1N(k,2)\leq \lfloor T_2(k)\rfloor+1, where T2(k)=2(k2−1)(k−1)(2k+1)/(k−3)T_2(k)=2(k^2-1)(k-1)(2k+1)/(k-3).
Polynomial bound for k\sqrt{k}For every integer k≥2k\geq2, the minimum exists and N(k,k)≤⌊Ts(k)⌋+1N(k,\sqrt{k})\leq\lfloor T_s(k)\rfloor+1, where Ts(k)=43(k2−k+1)(k−1)(k(k−1)+1)T_s(k)=\frac43(k^2-k+1)(k-1)(k(k-1)+1).
Finite minimum at 2P(2,2,3)P(2,2,3) holds, while P(2,2,M)P(2,2,M) fails for every positive integer M<3M<3; hence N(2,2)=3N(2,2)=3.
Finite minimum at 3P(3,2,9)P(3,2,9) holds, while P(3,2,M)P(3,2,M) fails for every positive integer M<9M<9; hence N(3,2)=9N(3,2)=9.
Finite minimum at 4P(4,2,13)P(4,2,13) holds, while P(4,2,M)P(4,2,M) fails for every positive integer M<13M<13; hence N(4,2)=13N(4,2)=13.
One-term target 2For every positive integer NN, P(1,2,N)P(1,2,N) fails; N(1,2)N(1,2) does not exist.
One-term target 1P(1,1,1)P(1,1,1) holds and the least positive length is N(1,1)=1N(1,1)=1.
Exponential bound for 2For every integer k≥2k\geq2, N(k,2)N(k,2) exists and is at most 16k16^k. The one-term target 2 is expressly excluded.
Exponential bound for k\sqrt{k}For every integer k≥1k\geq1, N(k,k)N(k,\sqrt{k}) exists and is at most 64k64^k, including the actual one-term minimum.

All divisions defining T2,TsT_2,T_s are real divisions before applying the ordinary integer floor. No natural-number division is substituted. Translating every index by one gives exactly the same minima for {1,…,N}\{1,\ldots,N\}. Cyclic progressions used below do not themselves establish any final assertion.

Common derivations: finite Fourier and Fejér identities

Fix a positive integer NN and a sign coloring ff, extended periodically to the integers. Write

Sd(a)=∑j=0k−1f((a+jd) mod N),Md=1N∑a=0N−1Sd(a)2.S_d(a)=\sum_{j=0}^{k-1}f((a+jd)\bmod N),\qquad M_d=\frac1N\sum_{a=0}^{N-1}S_d(a)^2.

Finite Fourier normalization

Take ω=exp⁡(2πi/N)\omega=\exp(2\pi i/N). For t,u∈{0,…,N−1}t,u\in\{0,\ldots,N-1\}, put q=ωt−uq=\omega^{t-u}. If t=ut=u, the sum of qaq^a is NN. Otherwise NN cannot divide the nonzero integer t−ut-u in this range, so q≠1q\neq1, while qN=1q^N=1. Multiplying the finite geometric sum by 1−q1-q gives 1−qN=01-q^N=0. Thus

1N∑a=0N−1ω(t−u)a=1{t=u}.(1)\frac1N\sum_{a=0}^{N-1}\omega^{(t-u)a}=\mathbf1_{\{t=u\}}. \tag{1}

For N=1N=1 only the first case occurs.

Define

f^(t)=1N∑a=0N−1f(a)ω−ta.\widehat f(t)=\frac1N\sum_{a=0}^{N-1}f(a)\omega^{-ta}.

Interchanging two finite sums and applying the same geometric identity with the roles of index and frequency exchanged gives f(x)=∑tf^(t)ωtxf(x)=\sum_t\widehat f(t)\omega^{tx}. For arbitrary complex coefficients ctc_t, direct multiplication gives

1N∑a∣∑tctωta∣2=∑t,uctcu‾1N∑aω(t−u)a=∑t∣ct∣2.(2)\frac1N\sum_a\left|\sum_t c_t\omega^{ta}\right|^2 =\sum_{t,u}c_t\overline{c_u} \frac1N\sum_a\omega^{(t-u)a} =\sum_t|c_t|^2. \tag{2}

In particular ∑t∣f^(t)∣2=1\sum_t|\widehat f(t)|^2=1.

With Gd(z)=∑j=0k−1zjdG_d(z)=\sum_{j=0}^{k-1}z^{jd}, the periodic expansion of ff yields

Sd(a)=∑tf^(t)ωtaGd(ωt),Md=∑t∣f^(t)∣2∣Gd(ωt)∣2.(3)S_d(a)=\sum_t\widehat f(t)\omega^{ta}G_d(\omega^t),\qquad M_d=\sum_t|\widehat f(t)|^2|G_d(\omega^t)|^2. \tag{3}

This independently supplies the normalization and finite basis/Parseval content used in the source. It holds for every positive NN and every natural dd, with no primality, coprimality or distinct-residue assumption.

Fejér expansion and the factor two

For a unit complex number zz, integers k,D≥0k,D\geq0, and 1≤d≤D1\leq d\leq D, let wd=1−d/(D+1)w_d=1-d/(D+1). Consider

Q=1D+1∑p,q=0k−1∣∑r=0D(zpzq‾)r∣2.Q=\frac1{D+1}\sum_{p,q=0}^{k-1} \left|\sum_{r=0}^{D}(z^p\overline{z^q})^r\right|^2.

Every summand is nonnegative. When p=qp=q, its value after division by D+1D+1 is D+1D+1, since zpzp‾=1z^p\overline{z^p}=1. Therefore Q≥k(D+1)Q\geq k(D+1), even when different powers zpz^p coincide.

Expand the square and interchange the four finite sums. For fixed r,sr,s, the sum over p,qp,q is

∣∑p=0k−1zp(r−s)∣2.\left|\sum_{p=0}^{k-1}z^{p(r-s)}\right|^2.

Negative exponents are well-defined because z≠0z\neq0. Their sums are the conjugates of the positive-exponent sums, and have the same squared modulus. There are D+1D+1 pairs with r=sr=s. For a positive difference dd, the pairs (r,s)=(s+d,s)(r,s)=(s+d,s) number exactly D+1−dD+1-d, and there are equally many pairs of difference −d-d. It follows that

Q=k2+2∑d=1Dwd∣Gd(z)∣2.(4)Q=k^2+2\sum_{d=1}^{D}w_d|G_d(z)|^2. \tag{4}

Consequently

∑d=1Dwd∣Gd(z)∣2≥k(D+1)−k22.(5)\sum_{d=1}^{D}w_d|G_d(z)|^2 \geq \frac{k(D+1)-k^2}{2}. \tag{5}

Since 0≤wd≤10\leq w_d\leq1, the same lower bound holds for ∑d=1D∣Gd(z)∣2\sum_{d=1}^{D}|G_d(z)|^2.

This includes the empty D=0D=0 case: the identity gives Q=k2Q=k^2, while the lower bound becomes 0≥(k−k2)/20\geq(k-k^2)/2 for natural kk. No limiting argument is involved.

As an exact normalization attack, take k=2,D=4,z=−1k=2,D=4,z=-1. Then G1=G3=0G_1=G_3=0 and G2=G4=2G_2=G_4=2, so the weighted energy is 16/516/5. Directly, the two diagonal pair terms total 1010, and each off-diagonal term is 1/51/5, giving Q=52/5=4+2(16/5)Q=52/5=4+2(16/5). This tests the normalization, diagonal contribution and factor two away from the all-ones case. The general proof above, rather than this example, establishes (4)–(5).

Multiplying (5) by the nonnegative masses ∣f^(t)∣2|\widehat f(t)|^2 and summing over tt gives

∑d=1DwdMd≥k(D+1)−k22,∑d=1DMd≥k(D+1)−k22.(6)\sum_{d=1}^{D}w_dM_d\geq\frac{k(D+1)-k^2}{2},\qquad \sum_{d=1}^{D}M_d\geq\frac{k(D+1)-k^2}{2}. \tag{6}

The masses sum to exactly one, not NN or 1/N1/N.

The source's conditional helpers with a scalar Cassels hypothesis are discharged by its own scalar proof. In the supplied Basic slice, the nonnegative pair terms, expansion and bounds lead to casselsGeomLowerClaim_true, then to the unconditional moment bound. The Sqrt slice retains the exact weighted identity. No Cassels or Turán literature result is imported into this examination.

Common derivations: ordinary progressions, wrapping and minima

Wrap loss and target conventions

Let m=(k−1)dm=(k-1)d. Among a=0,…,N−1a=0,\ldots,N-1, exactly min⁡(N,m)\min(N,m) satisfy a+m≥Na+m\geq N: if m<Nm<N, they are N−m,…,N−1N-m,\ldots,N-1; if m≥Nm\geq N, all starts qualify. In particular their number is at most mm. Equality at the endpoint a+m=Na+m=N belongs to the wrapping set.

For every cyclic start, the triangle inequality gives ∣Sd(a)∣≤k|S_d(a)|\leq k, even if residues repeat. If every non-wrapping start has Sd(a)2≤bS_d(a)^2\leq b, then, for k2−b≥0k^2-b\geq0,

Md≤b+(k2−b)min⁡(N,(k−1)d)N≤b+(k2−b)(k−1)dN.(7)M_d\leq b+(k^2-b)\frac{\min(N,(k-1)d)}N \leq b+(k^2-b)\frac{(k-1)d}{N}. \tag{7}

The second estimate remains valid when its right side exceeds k2k^2. No implicit assumption (k−1)d<N(k-1)d<N was used to count wrapping starts.

For discrepancy 2, failure of the non-strict target means integer ∣Sd(a)∣<2|S_d(a)|<2, hence Sd(a)2≤1S_d(a)^2\leq1. For the other target, both k\sqrt{k} and ∣Sd(a)∣|S_d(a)| are nonnegative, and squaring preserves their order. Thus

k≤∣Sd(a)∣⟺k≤Sd(a)2.(8)\sqrt{k}\leq|S_d(a)|\quad\Longleftrightarrow\quad k\leq S_d(a)^2. \tag{8}

Failure gives the integer inequality Sd(a)2≤k−1S_d(a)^2\leq k-1. The caps in (7) are therefore b=1b=1 and b=k−1b=k-1, respectively. Equality in (8) remains admissible, including square kk. For example a four-term sum 1+1+1−1=21+1+1-1=2 reaches 4\sqrt4; replacing the final comparison by a strict one would change the subject.

If a+(k−1)d<Na+(k-1)d<N and j<kj<k, then a+jd≤a+(k−1)d<Na+jd\leq a+(k-1)d<N. Every cyclic index equals its ordinary index. For d≥1d\geq1 the indices are distinct. The canonical representatives of Z/NZ\mathbb Z/N\mathbb Z are in bijection with {0,…,N−1}\{0,\ldots,N-1\}, so transport through Fin and ZMod changes neither the sum nor its normalization. An integer embedded in C\mathbb C has squared norm equal to its integer square embedded in R\mathbb R. These observations supply every model bridge used in (3), (6) and (7).

Polynomial bound for discrepancy 2

Assume k≥5k\geq5 and that every ordinary kk-term AP misses target 2. Put D=2kD=2k. Summing (7) with b=1b=1 and dividing by DD gives

1D∑d=1DMd≤1+(k2−1)(k−1)(D+1)2N=:U2.\frac1D\sum_{d=1}^D M_d \leq 1+\frac{(k^2-1)(k-1)(D+1)}{2N} =:U_2.

The unweighted half of (6) gives

1D∑d=1DMd≥k+14=:L2.\frac1D\sum_{d=1}^D M_d\geq\frac{k+1}{4}=:L_2.

Writing A2=(k2−1)(k−1)(2k+1)A_2=(k^2-1)(k-1)(2k+1), subtraction gives the exact gap

L2−U2=N(k−3)−2A24N=k−34(1−T2(k)N).(9)L_2-U_2 =\frac{N(k-3)-2A_2}{4N} =\frac{k-3}{4}\left(1-\frac{T_2(k)}N\right). \tag{9}

Both NN and k−3k-3 are positive. Therefore N>T2(k)N>T_2(k) makes the gap strictly positive, a contradiction. The conclusion is an ordinary AP with 1≤d≤2k1\leq d\leq2k and non-strict discrepancy at least 2.

A floor boundary attack is decisive about the needed strictness: T2(5)=1056T_2(5)=1056. At N=1056N=1056, (9) is zero and this contradiction is unavailable. The stated choice is N=1057N=1057, where the gap is exactly 1/2114>01/2114>0. Thus the added one is doing necessary work in the argument; it was not lost when passing between real and integer bounds.

Polynomial bound for discrepancy k\sqrt{k}

Assume k≥2k\geq2 and every ordinary AP fails (8). The exact finite sums, obtained from ∑d=D(D+1)/2\sum d=D(D+1)/2 and ∑d2=D(D+1)(2D+1)/6\sum d^2=D(D+1)(2D+1)/6, are

∑d=1Dwd=D2,∑d=1Dd wd=D(D+2)6.(10)\sum_{d=1}^D w_d=\frac D2,\qquad \sum_{d=1}^D d\,w_d=\frac{D(D+2)}6. \tag{10}

Nonnegativity of every weight permits summing (7). Set A=(k2−k+1)(k−1)A=(k^2-k+1)(k-1) and K=k(k−1)>0K=k(k-1)>0, and take D=2KD=2K. The weighted bounds become

Us=(k−1)D2+AD(D+2)6N,Ls=k(D+1)−k22.U_s=(k-1)\frac D2+\frac{A D(D+2)}{6N},\qquad L_s=\frac{k(D+1)-k^2}{2}.

Before inserting the error term, the difference is Ls−(k−1)D/2=(D−K)/2=K/2L_s-(k-1)D/2=(D-K)/2=K/2. Hence

Ls−Us=K2−2AK(K+1)3N=K2(1−Ts(k)N).(11)L_s-U_s =\frac K2-\frac{2AK(K+1)}{3N} =\frac K2\left(1-\frac{T_s(k)}N\right). \tag{11}

For N>Ts(k)N>T_s(k) this is strictly positive, again a contradiction. It produces a positive difference at most 2k(k−1)2k(k-1) and a non-wrapping ordinary AP satisfying (8).

At the smallest allowed k=2k=2, the threshold is the integer 1212. At N=12N=12 the gap is zero, while at the stated integer choice 1313 it is 1/131/13. The proof uses the exact weighted estimate and the integer cap k−1k-1; replacing either by a heuristic average would not prove (11).

Existence, floors and least values

On their stated domains, both thresholds are positive real numbers. For either threshold TT, let B=⌊T⌋+1B=\lfloor T\rfloor+1. Then B≥1B\geq1 and T<BT<B, including integral TT. The preceding contradiction proves the universal property at BB before selecting a minimum. The nonempty set of positive successful lengths therefore has a least element, and that element is at most BB.

The source properties explicitly require positive length. Consequently their Nat.find selections over natural numbers are these same positive minima. On the positive threshold domains, Nat.floor agrees with the ordinary floor. No default value supplies existence. N176 is guarded by k≥5k\geq5, and N176Sqrt by k≥2k\geq2; their default zero values outside those guards are different definitions from the mathematical minima.

For completeness, if the property holds at MM and N≥MN\geq M, restricting a coloring of length NN to its first MM entries supplies an AP still contained in the larger interval. Translation by one is also bijective: set g(x)=f(x−1)g(x)=f(x-1), send (a,d)(a,d) to (a+1,d)(a+1,d), and reverse by subtraction. Both successful-length sets, and hence their minima, are unchanged.

Finite bases: exact independent reproduction

Boolean codes and sign colorings

For any N≥0N\geq0, encode a sign coloring by

c=∑{x:f(x)=1}2x.c=\sum_{\{x:f(x)=1\}}2^x.

Then 0≤c<2N0\leq c<2^N since ∑x=0N−12x=2N−1\sum_{x=0}^{N-1}2^x=2^N-1. For a fixed xx, split the sum as c=c<x+ϵx2x+2x+1tc=c_{<x}+\epsilon_x2^x+2^{x+1}t, where 0≤c<x<2x0\leq c_{<x}<2^x and ϵx\epsilon_x is one or zero according as f(x)=1f(x)=1 or −1-1. Then (cdiv2x) mod 2=ϵx(c\mathbin{\mathrm{div}}2^x)\bmod2=\epsilon_x. Conversely repeated Euclidean division by two gives each 0≤c<2N0\leq c<2^N exactly NN binary digits, padded with zeros; their reconstruction gives cc. Thus these codes and sign colorings are bijective. This includes the empty coloring and the sole code zero at N=0N=0.

For k≥2k\geq2, an admissible positive difference satisfies d≤(k−1)d≤a+(k−1)d<Nd\leq(k-1)d\leq a+(k-1)d<N. Also a<Na<N. Thus the source loops over a,d<Na,d<N, with the positive-difference guard, exhaust all ordinary APs. Its endpoint guard implies every j<kj<k is in range, so the fold skips no term on an accepted candidate. The Boolean predicate goodCode is exactly the universal coloring property on these finite domains. allBeforeFalse rejects every smaller length. At N=0N=0, one empty coloring exists but there is no start, so the property fails. The mathematical bridge is proved here; no claim is made that the source has formalized this bridge.

The author checker enumerates sign tuples and equal-gap subsets, then compares with its start/difference inventory. Its integer arithmetic, positive endpoint conditions, empty cases, target comparison and failure exit were inspected. The unchanged script was freshly run through the supplied runtime, producing 12 passing checks and exactly the retained 28 data rows. Actual script-file import tracing identified all 17 runtime files at the supplied paths. Neither a stored success message nor native_decide was used as a premise.

Independent inclusion-exclusion for k=2,3k=2,3

For k=2k=2, a sum reaches absolute value 2 exactly when the two signs agree. For k=3k=3, its absolute value is 1 or 3, so reaching 2 is equivalent to all three signs agreeing. Avoidance is therefore absence of monochromatic AP edges in both cases.

Generate an AP by its endpoints x<yx<y: it exists precisely when k−1k-1 divides y−xy-x, with points x+j(y−x)/(k−1)x+j(y-x)/(k-1). This is separate from both author generators. For any selected subset JJ of AP edges, requiring every edge of JJ to be monochromatic identifies its vertices into c(J)c(J) equivalence classes. There are exactly 2c(J)2^{c(J)} sign assignments satisfying those equalities. Inclusion-exclusion gives the number of avoiding colorings:

Ak,N=∑J⊆E(−1)∣J∣2c(J).(12)A_{k,N}=\sum_{J\subseteq E}(-1)^{|J|}2^{c(J)}. \tag{12}

The independent implementation starts with the discrete partition and coefficient one. For each edge it keeps each current term, and subtracts the same coefficient on the partition obtained by merging that edge's classes. Induction on the number of processed edges proves that the resulting coefficient of each partition is exactly the sum of the inclusion-exclusion signs producing it. Equal partitions can therefore be combined without enumerating sign tuples. This is a terminating expansion over a finite edge list, not an assumption that all colorings have been visited.

For prescribed prefix signs, a partition contributes zero if a class receives both signs. Otherwise each unfixed class has two choices. Using these conditional counts, the program selects sign −1-1 whenever that branch has a completion, and sign +1+1 otherwise. The two branch counts sum to the parent count. This constructs the lexicographically first avoiding coloring and records its exact branch counts. No author witness is supplied to this construction.

At (k,N)=(2,3)(k,N)=(2,3) the resulting coefficient polynomial is q3−3q2+2qq^3-3q^2+2q, whose value at q=2q=2 is zero. At (3,9)(3,9) it is

q9−16q7+21q6+42q5−101q4+58q3+5q2−10q.(13)q^9-16q^7+21q^6+42q^5-101q^4+58q^3+5q^2-10q. \tag{13}

Its value at 2 is 512−2048+1344+1344−1616+464+20−20=0512-2048+1344+1344-1616+464+20-20=0. The retained data supplies the endpoint edges and coefficient polynomial for every checked length; rerunning reconstructs the partition expansion.

There is also a direct independent proof at k=2k=2: among three signs two agree, and any pair of distinct indices is a positive-difference two-term AP. The opposite signs at length two show the lower bound.

Independent recurrence for k=4k=4

A four-term signed sum misses absolute value 2 exactly when it is zero. In particular every consecutive block of four must sum to zero. Subtracting neighboring block equations gives f(i+4)=f(i)f(i+4)=f(i) whenever both indices occur.

For 4≤N≤64\leq N\leq6, the first four entries must be a balanced seed with two signs of each kind, of which there are six. The recurrence determines any remaining entries, and only difference one is possible, so all six work.

For 7≤N≤127\leq N\leq12, the AP 0,2,4,60,2,4,6 has sum 2(f(0)+f(2))2(f(0)+f(2)). It must vanish, so f(2)=−f(0)f(2)=-f(0). The balanced seed then forces f(3)=−f(1)f(3)=-f(1). Every avoiding coloring is therefore the restriction of

(u,v,−u,−v,u,v,−u,−v,…),u,v∈{−1,1}.(14)(u,v,-u,-v,u,v,-u,-v,\ldots),\qquad u,v\in\{-1,1\}. \tag{14}

Conversely all four choices work through length 12. Every admissible difference is at most 3. An odd difference visits each residue class modulo four once; difference two alternates opposite signs. Both sums are zero.

At length 13, the positive-difference AP 0,4,8,120,4,8,12 lies in the interval and has sum 4u4u, eliminating all four possibilities. At length 12 its last point is outside the interval, so it cannot be used early. For N<4N<4, there are no four-term APs and all 2N2^N colorings avoid.

This proves the count formula used by the independent program. The zero at 13 follows from the exhibited obstruction to all recurrence seeds; it is not inferred from a hard-coded assertion of the desired minimum. The program retains the allowable seeds and checks its first witnesses against the endpoint-generated APs.

Complete count and witness coverage

kkLengths, in orderNumbers of avoiding colorings, in that order
20,…,30,\ldots,31,2,2,01,2,2,0
30,…,90,\ldots,91,2,4,6,10,14,20,16,6,01,2,4,6,10,14,20,16,6,0
40,…,130,\ldots,131,2,4,8,6,6,6,4,4,4,4,4,4,01,2,4,8,6,6,6,4,4,4,4,4,4,0

Every AP count, coloring-domain size, avoiding count and first avoiding coloring agrees between the fresh author route and the independent route, in all 28 rows. The independent route represents 17,421 assignments; it does not enumerate 17,421 sign tuples. The separate AP count formula is mN−(k−1)m(m+1)/2mN-(k-1)m(m+1)/2, with m=max⁡(0,⌊(N−1)/(k−1)⌋)m=\max(0,\lfloor(N-1)/(k-1)\rfloor). Indeed, each 1≤d≤m1\leq d\leq m permits exactly N−(k−1)dN-(k-1)d starts, and no larger difference permits a start. Summing these counts gives the formula; each AP has a unique start and positive difference.

The first avoiding witnesses at one below each minimum are, respectively, (−1,1)(-1,1), (−1,−1,1,1,−1,−1,1,1)(-1,-1,1,1,-1,-1,1,1), and (−1,−1,1,1,−1,−1,1,1,−1,−1,1,1)(-1,-1,1,1,-1,-1,1,1,-1,-1,1,1). All earlier lengths have positive counts, and the claimed upper lengths have count zero. This establishes each exact positive minimum.

The negative input asks for minima 2, 8 and 12 at k=2,3,4k=2,3,4. It was executed under Python -O and exited 1, with respective avoiding counts 2, 6 and 4 and concrete witnesses. Thus each computational case has an observed failing input at the relevant boundary. For the author's separate predicates, an omitted AP such as (0,1)(0,1) at k=2,N=2k=2,N=2 would fail inventory agreement; reporting (−1,−1)(-1,-1) there as an avoider would fail witness validation; the false upper lengths above fail universality; a proposed minimum of 4 at k=2k=2 fails its smaller-length test because length 3 already has zero avoiders. These describe failure conditions, not modifications made to the frozen author program.

The independent route changes both the counted objects and the arithmetic primitive. A sign-loop stopping or bit-coverage error cannot silently remove the same assignments from the partition inclusion-exclusion calculation. The four-term recurrence avoids a full assignment census altogether. Their endpoint inventory and the closed AP-count formula also differ from the author's subset and bounded-start inventories. Agreement alone is not the warrant: equations (12), the partition induction, the conditional-count argument and the proof of (14) provide the mathematical reductions.

One-term cases and exponential consequences

For k=1k=1, every admissible sum is a single sign, of absolute value one. Thus for every positive NN no coloring has a one-term AP of discrepancy 2, and the universal property for target 2 fails. There is no N(1,2)N(1,2).

For target 1=1\sqrt1=1, at length one take a=0,d=1a=0,d=1. Its endpoint is zero and its absolute sum is one, including equality. Since every positive length is at least one, the minimum is N(1,1)=1N(1,1)=1. The source default N176Sqrt 1 = 0 has no role in this argument.

For integers k≥5k\geq5, the positive factors satisfy k−3≥k/3k-3\geq k/3, k2−1≤k2k^2-1\leq k^2, k−1≤kk-1\leq k and 2k+1≤3k2k+1\leq3k. Therefore

T2(k)≤18k3,⌊T2(k)⌋+1≤18k3+1≤19k3.(15)T_2(k)\leq18k^3,\qquad \lfloor T_2(k)\rfloor+1\leq18k^3+1\leq19k^3. \tag{15}

For every integer k≥1k\geq1, k≤2kk\leq2^k: start at one and use k+1≤2k≤2k+1k+1\leq2k\leq2^{k+1} in the induction step. For k≥5k\geq5, also 19≤2k19\leq2^k, since 19≤3219\leq32 and powers of two increase. Hence

19k3≤2k(2k)3=16k.19k^3\leq 2^k(2^k)^3=16^k.

At k=2,3,4k=2,3,4, the independently established minima are 3≤2563\leq256, 9≤40969\leq4096, and 13≤6553613\leq65536. These cover exactly the remaining domain of the exponential bound for 2. No assertion for k=1k=1 is imported.

For k≥2k\geq2, the three factors in TsT_s satisfy k2−k+1≤k2k^2-k+1\leq k^2, k−1≤kk-1\leq k, and k(k−1)+1≤k2k(k-1)+1\leq k^2. Thus

Ts(k)≤43k5,⌊Ts(k)⌋+1≤43k5+1≤3k5.(16)T_s(k)\leq\frac43 k^5,\qquad \lfloor T_s(k)\rfloor+1\leq\frac43k^5+1\leq3k^5. \tag{16}

Now 3≤2k3\leq2^k and k≤2kk\leq2^k, so 3k5≤2k(2k)5=64k3k^5\leq2^k(2^k)^5=64^k. The remaining k=1k=1 case is the actual minimum 1≤641\leq64 just proved. These are uniform inequalities for every parameter in the stated ranges, not extrapolations from finite tests.

Weakest steps and strongest attempted refutations

The following table identifies at most three weakest links for each conclusion. The derivations above supply the links; the last column states their composition and the attempted break, rather than relying on agreement with source output.

ConclusionWeakest steps independently rederivedStrongest attack and result
Polynomial bound for 2(1) Geometric orthogonality and the normalized Fourier moment, (1)–(3); (2) the pair-energy diagonal and both difference multiplicities, (4)–(6); (3) wrap loss, positive gap (9), and the strict floor/minimum bridge.Try to concentrate all large cyclic sums on wrapping progressions. The alternating six-point example below shows why this is a real threat. Exact wrap counting and the gap in (9) defeat it whenever the stated threshold is exceeded, for every coloring. The integral threshold at k=5k=5 also tests the required strict inequality. No defect found.
Polynomial bound for k\sqrt{k}(1) The exact weighted identity and nonnegative Fourier masses; (2) integer-square cap k−1k-1, exact weight sums (10), and gap (11); (3) non-wrapping transport, equality in the square-root target, and the floor/minimum bridge.Try to use a square kk to reverse a strict/non-strict comparison, or lose an endpoint in the wrap estimate. Equation (8) includes equality, and a last point equal to NN is counted as wrapping. The period-four example below fails only after its obstructing AP enters the interval. The smallest-domain gap is positive at k=2,N=13k=2,N=13. No defect found.
N(2,2)=3N(2,2)=3(1) All sign colorings are represented by codes; (2) any pair is an ordinary two-term AP, so pigeonhole gives the upper value; (3) opposite signs give the lower value and (12) reproduces all counts.Try to advance the minimum to 2. The retained witness (−1,1)(-1,1) defeats it, and the negative control detects two avoiders. Try to leave an avoider at 3: pigeonhole and the zero partition count separately rule it out. No defect in the stated minimum found.
N(3,2)=9N(3,2)=9(1) Missing discrepancy 2 is precisely a nonmonochromatic coloring of the triple constraints; (2) partition inclusion-exclusion counts every assignment with its exact sign; (3) the zero in (13), positive smaller counts and constructed witnesses imply the minimum.Try to extend an avoiding length-eight pattern to a length-nine counterexample, or miss one through the author's sign enumeration. The independent constraint expansion gives zero at 9 without that enumeration, while the false minimum 8 is rejected with six avoiders. All nine-point endpoint constraints and the polynomial coefficients are retained. No defect found.
N(4,2)=13N(4,2)=13(1) Zero sums of neighboring four-blocks force period four; (2) the difference-two AP reduces the six balanced seeds to four; (3) difference four at length 13 eliminates every seed, whereas every allowed difference through length 12 gives sum zero.Try to keep a balanced period-four sequence forever, or use 0,4,8,120,4,8,12 at length 12. It is excluded from length 12 and included at 13, where its sum is 4u4u. The false minimum 12 leaves four witnesses; the obstruction proves none survives at 13. No defect found.
Nonexistence of N(1,2)N(1,2)The one-term sum has absolute value one for every start and coloring; positive length always has at least one coloring.Try to make a very large interval or positive difference change a one-term sum. Neither changes its single value. The target 2 is impossible at every positive length. No defect found.
N(1,1)=1N(1,1)=1The admissible choice a=0,d=1a=0,d=1 works at length one for both signs; one is the smallest positive integer.Try to substitute the source's default N176Sqrt 1 = 0 or to demand two distinct indices from a one-term AP. Neither matches the statement. Its actual endpoint is a+0d=0a+0d=0, and equality at discrepancy one is allowed. No defect found.
Exponential bound 16k16^k(1) The polynomial conclusion supplies existence for k≥5k\geq5; (2) the rounding estimate (15) and induction k≤2kk\leq2^k prove the uniform comparison; (3) the three separately verified finite minima cover exactly k=2,3,4k=2,3,4.Try to leave a gap before the polynomial domain or extend the conclusion to the nonexistent k=1k=1 case. The three bases fill the former and the statement explicitly excludes the latter. The constant 1919 is absorbed only from k=5k=5, where 2k≥322^k\geq32. No defect found.
Exponential bound 64k64^k(1) The square-root polynomial conclusion supplies existence for k≥2k\geq2; (2) (16) and 3≤2k3\leq2^k, k≤2kk\leq2^k prove the uniform comparison; (3) the actual N(1,1)=1N(1,1)=1 covers the remaining parameter.Try to use the guarded zero fallback as the base or apply 3≤2k3\leq2^k at k=1k=1. Neither is used: the separate one-term proof supplies that case. No defect found.

The most consequential attempted refutation was the cyclic-to-ordinary passage. For k=5,N=6k=5,N=6, the alternating coloring f(a)=(−1)af(a)=(-1)^a has only difference-one ordinary five-term APs, each of absolute sum one. On the cycle, every even difference gives absolute sum five. Thus a large cyclic moment alone cannot entail the ordinary conclusion. This is an exact counterexample to that shortcut, not to the commissioned bound. Extending the alternating coloring to any interval of length at least 9 already supplies the ordinary AP 0,2,4,6,80,2,4,6,8 of absolute sum five. More generally, (7) accounts for every possible wrapping start, and (9) leaves a strictly positive gap at every stated polynomial length, including 1/21141/2114 at k=5,N=1057k=5,N=1057.

The same failure mechanism is visible for k=4k=4 and the coloring with period (−1,−1,1,1)(-1,-1,1,1): at length four the ordinary sum is zero, while cyclic difference four has absolute sum four. The exact recurrence analysis shows that it avoids target 2, which equals 4\sqrt4, through length 12 and fails at length 13. It therefore checks the model and endpoint obstruction without purporting to refute the much larger square-root polynomial bound. These examples test a mechanism the proof must control; merely finding large cyclic sums would have missed it.

Additional attacks covered composite NN, non-coprime and repeated cyclic steps, N=1N=1, empty D=0D=0, saturated wrap sets, the nonnegative coefficient k2−bk^2-b, natural subtraction before real coercion, and integral thresholds. The Fourier proof requires only N>0N>0. Natural subtractions used in the public ranges agree with their integer differences: k−1≥0k-1\geq0, k−3>0k-3>0, and k2−(k−1)=k2−k+1>0k^2-(k-1)=k^2-k+1>0. No discarded exceptional coloring or unstated arithmetic restriction survived these checks.

Premises, interfaces and actual reading depth

The premise list was derived from the frozen statement, proof, source slices and every consequence sentence. There is no consumed native L-claim and no accepted external Cassels, Turán, van der Waerden or other source theorem being taken as a black box. The elementary finite identities, integer inequalities and well-ordering used here are stated and derived at their points of use. The exact external source versions are identified in the subject block. The following table distinguishes the source interfaces from any claim of formal execution.

Input interface and locator in the preserved subjectHypotheses and consumed contentReading and verification scope
Basic, lines 12–244: cyclicIndex, cyclicAPSum, wraps, ordinaryAPSum, card_wrapStarts_le and moment upper estimatesPositive NN; integer signs; d≥1d\geq1 when returning an AP. Pointwise bound k2k^2, endpoint guard and count of wrapping starts.Whole text read; mathematical deductions rederived in (7) and the ordinary-index argument. No coprimality restriction is added.
Basic, lines 246–739: fejerPairEnergy through casselsGeomLowerClaim_trueUnit zz, natural k,Dk,D. Pair terms are nonnegative; diagonal contribution and finite triangle sums yield the scalar lower bound.Whole text read; full finite four-sum expansion and difference counts rederived in (4)–(5). Conditional scalar helpers are discharged, not assumed.
Basic, lines 741–1108: fourierCoeff, expansions, orthogonality and unconditional moment lower boundsPositive finite cyclic group; signs give unit squared mass.Whole text read; normalized geometric orthogonality, inversion, Parseval and moment expansion rederived in (1)–(3),(6). No unread Fourier theorem is an external premise.
Basic, lines 1110–1324: finZModEquiv, zmodColoringOfFin and cyclic momentsCanonical representatives and integer-to-complex coercion preserve every sum, norm square and average.Whole text read; the explicit bijection and normalization are checked above.
Basic, lines 1326–1702: real threshold, ordinary existence, htmlBoundNat, erdos176Good, erdos176Number, N176_le_report_bound_explicitk≥5k\geq5, real threshold, positive length, every sign map. Establish a successful length before the least element. N176's zero branch is outside the theorem's range.Whole text read; gap (9), positivity, real floor, existence and least-value interface verified. The final declaration has no outstanding Cassels hypothesis.
Sqrt, lines 12–260: fejerWeight, its two sums, triangle multiplicities and fejerPairEnergy_eq_sq_add_two_weightedNatural DD, 1≤d≤D1\leq d\leq D, unit zz. Nonnegative weights and exact weighted scalar bound.Whole text read; (4)–(5),(10) rederive every required finite identity.
Sqrt, lines 262–766: weighted cyclic lower bound, sqrtLargeSq, moment upper estimates and ordinary existencePositive NN, k≥2k\geq2, squared integer target. Common Basic identities plus integer cap k−1k-1 and weighted wrap loss.Whole text read; (6)–(8),(10)–(11) establish the complete interface, including the non-strict square-root comparison.
Sqrt, lines 768–964: sqrtHtmlBoundNat, erdos176SqrtGood, least number and N176Sqrt_le_report_bound_explicitk≥2k\geq2; successful positive length before Nat.find. Default zero below two is not a minimum assertion.Whole text read; floors, positivity and the guarded abbreviation checked separately from the actual one-term minimum.
SmallKCommon, lines 1–45; K2, K3, K4, each lines 1–23Boolean sign codes, bounded positive differences, exactAtCode = goodCode together with allBeforeFalse.Whole text read. The ordinary-sign bridge is supplied above. The native_decide invocations were neither run nor used as warrants; the exact finite claims were freshly re-established by both computational routes.
K1, lines 1–27; exponential deductions, lines 1–15A single signed value has magnitude one; positive minimum and polynomial comparisons on the stated domains.Whole text read; both one-term claims and both infinite consequences proved above with every base.
Candidate proof, lines 1–148; statement, lines 1–24Ordinary APs, non-strict targets, real division, positive minima, translation, both polynomial and exponential conclusions.Whole text read, including every supplied consequence and cut marker. No omitted standing or author assurance is consumed.
Finite checker, lines 1–93; fixture, lines 1–359Exact inputs (2,3),(3,9),(4,13)(2,3),(3,9),(4,13) and all lengths from zero to each bound.Whole text and fixture read. Unchanged checker rerun; every concrete data row independently reproduced. Scope is exactly those finite cases.
Supplied runtime closureChecker, evidence_parser and their import closure needed by the unchanged script.All 17 files read whole, including import/initialization behavior. Only the named checker route executed. No claim about uncalled gate, ledger, audit or corpus utilities.
Manifest and provenance, wholeExtraction identity, cut, source versions, credits and stated licensing limits.Whole read. These identify material; they do not establish a theorem, a source build or equality with an unlisted archive file.

Dependency reading at verdict filing, 2026-10-15 UTC: the consumed-native-claim set is empty. A live ledger read is therefore inapplicable and was excluded by the commission; no stale or pending native premise is silently being relied on. No pending source grade is assumed. All substantive mathematical interfaces in the table are within this examination.

The acyclic order for the batch is: common finite identities and model bridges; the two polynomial conclusions separately; the three finite minima and both one-term conclusions independently; then the exponential bound for 2 using its polynomial conclusion and the three finite minima, and the square-root exponential bound using its polynomial conclusion and the one-term minimum. The square-root polynomial proof uses common Basic identities, not the discrepancy-2 polynomial conclusion. The finite proofs use neither polynomial bound. Any grading of the consequences must preserve these dependencies and cannot substitute agreement on the last arithmetic line for acceptance of a consumed premise.

Checklist

Each row below applies to all nine restated conclusions. Where a failure mode has no corresponding mathematical operation, the inapplicability is stated explicitly. The claim-specific derivations and attacks in the preceding table supply the evidence for the shared verdicts.

Canonical failure modes

Failure modeVerdict and coverage
“Almost all” quietly upgraded to “all”Not found. The Fourier identities hold for each fixed coloring and every positive NN; no exceptional coloring is removed. The finite counts cover every assignment in each declared domain. Both one-term assertions quantify over all relevant signs and lengths. Exponential comparisons hold for every integer in their stated ranges.
Induction that presupposes terminationNot found. Inclusion-exclusion inducts over a finite, explicitly generated edge list; the witness construction runs through NN vertices. The only infinite-parameter induction proves k≤2kk\leq2^k with its base and successor step. The remaining proofs do not require iterative termination.
Probabilistic or averaging heuristics presented as proofsNot found. Equations (1)–(6) and (10) are exact finite sums. Nonnegative masses sum to one and wrap upper bounds are pointwise before averaging. There is no sampled probability estimate. Finite minima and one-term cases do not rely on a heuristic average.
Circular use of an equivalent targetNot found. The scalar pair estimate follows from nonnegative squares; successful lengths precede minimum selection. The finite independent counts do not assume the proposed minima, and the four-term zero at 13 follows from an explicit obstruction. The exponential consequences use the acyclic order stated above.
Exceptional sets dropped from density argumentsInapplicable: there is no density or asymptotic exceptional-set argument. The possible finite exceptional set of wrapping starts is instead counted exactly and paid for in (7); none is discarded.
Finite verification cited beyond base-case coverageNot found. The executable domain is exactly the 28 listed rows. Infinite polynomial and exponential families have symbolic proofs. The one-term universal claims are proved directly, not inferred from those rows.
Convergence of a relaxed or averaged system substituted for actual objectsNo convergence claim occurs, so its limit form is inapplicable. Its relevant model-transfer risk was attacked explicitly: (7) and the strict gaps force a non-wrapping ordinary AP, and the Boolean/sign and translation bridges preserve the exact target.

Named patterns

PatternVerdict and coverage
Model-class transport instead of entailmentThe classification/axiom-extension form is inapplicable: no new axiom system is classified. The related transfer question is discharged explicitly for Fin, cyclic representatives, ordinary indices, Boolean signs and translated intervals. The finite and one-term claims are in the original model.
Uniformity over an infinite family asserted from finitely many instancesNot found. Both polynomial gaps and both exponential comparisons are symbolic in kk with the displayed parameter dependence. No finite checks are used to infer these uniform bounds. The exact minima have finite, expressly bounded scope; one-term nonexistence is a direct formula for every NN.
Extremal claims audited in the claim's own unitsSatisfied. The exact minima are lengths in the ordinary AP model: positive lower witnesses and zero avoider counts at the upper lengths. Least positive values for the polynomials are formed only after existence. No optimality of polynomial or exponential constants is asserted; a zero source fallback is never counted as an attained minimum.
Consequence sentences are claim surfacesSatisfied. Both exponentials, all three finite minima, nonexistence at (1,2)(1,2), the value at (1,1)(1,1), translation and least-value deductions receive explicit arguments and separate conclusion verdicts. No stronger domain is inferred from neighboring statements.
Carry hypotheses actually used by a quantified argumentSatisfied. N>0N>0, k≥5k\geq5 or k≥2k\geq2, sign-valued colorings, positive ordinary difference, real divisions and non-strict targets are retained. All averages are finite. The k=1k=1 cases have separate proofs and do not enter formulas requiring k−3>0k-3>0 or k(k−1)>0k(k-1)>0.
A composition inherits its unproved premisesNo missing consumed clause found. Every interface is in the premise table, including Fourier normalization, wraps, integer caps, code surjectivity, floors, minima and bases. No unexecuted native_decide result or uninspected external theorem supplies a premise. The grading order for the consequences is explicit.
Reproducibility notes are claimsSatisfied for this examination's executable claims: the driver and exact inputs were freshly run, and actual script imports checked. All 28 rows and first witnesses agree. The unchanged checker's historical docstring path is expressly obsolete; it was not silently claimed runnable. The supplied runtime and current package-relative route below are the assessed rerun path.
Verifier quotations are claimsInapplicable to this blind subject. Prior reports and standing characterizations were excluded and unread; no earlier verifier ruling is quoted as evidence. This examination's own verdict words and coverage statements are given in full.
Verdict words spelled in fullSatisfied. Every conclusion below carries refutation-failed in full. No abbreviation merges it with the opposite verdict, refuted-as-stated; proof defective; statement unresolved is not used to mean a disproof.
Certified-bracket functions fail loudlyInapplicable: no approximate enclosure, numerical integration, iterative certificate or period-sensitive numerical window is used. All finite arithmetic is integral. Unsupported finite domains and malformed input raise an error with nonzero exit; no exhausted cap is returned as a certificate.
A harness leg with no failing input is decorationSatisfied for each finite case: the retained false minima 2, 8 and 12 fail with exact counts and witnesses, including under Python -O. Inventory disagreement and invalid-witness inputs are specified above; the driver's comparison rejects unequal data or wrong import origins. Analytic claims are derivations, not decorative executable legs.
A gate that reads caches instead of rerunning is defectiveNo gate is used as a mathematical warrant. The rerun driver executes both routes and controls first, then compares fresh data with the retained fixtures. The original fixture is concrete mathematical data, not an accepted success receipt.

Correlated-sample inference is inapplicable: no random sample, statistical confidence statement or repeated-run independence estimate appears. The evidence-coverage discipline is applied throughout: static mathematical proof coverage is separated from Lean execution, the exact finite rows from infinite families, and the independent route from both author algorithms. This is a first examination; the distinct-attack requirement for a second independent review cycle is inapplicable. Structural disjointness for the computational batch is supplied and justified.

Erdős whole-claim checklist

ItemVerdict and evidence
Quantifiers and scopeSatisfied for all nine conclusions. The restatement specifies every parameter range, every coloring, positive length, positive difference and non-strict target. Empty intervals occur only in the finite lower-bound checks; no positive minimum is zero.
CircularityNo circular step found. The pair-energy argument, finite expansion and recurrence supply foundations independent of the target; the batch composition is acyclic and existence precedes Nat.find.
Model and convention changesNo unsupported change found. The cyclic and Boolean models are connected explicitly to ordinary progressions; the translation to [1,N][1,N] is bijective. The alternating and period-four attacks test the failure of omitting this bridge.
Finite and statistical overreachNot found. Finite checks establish only the stated finite census and minima. Infinite bounds and one-term nonexistence are proved symbolically. Statistical inference is inapplicable.
UniformitySatisfied. All sum exchanges are finite. The exact gaps carry their full k,Nk,N dependence, and (15)–(16) give uniform comparisons on explicit domains. Finite census assertions are not promoted to uniform claims.
Extremal conclusionsSatisfied in interval-length units. Every exact minimum has an upper proof and lower witnesses; the other minima exist by well-ordering a nonempty positive set. Sharpness of the displayed general bounds is not claimed.
Consequences and compositionSatisfied subject to the stated acyclic grading order. Every consequence is individually attacked, including floors, both exponentials and all bases. No default abbreviation or source build supplies a missing link.
ComputationSatisfied for the finite claims: exact integer arithmetic, explicit bounded inputs, all 28 rows, concrete witnesses and polynomial/recurrence certificates, and observed nonzero negative controls. This item is otherwise inapplicable as proof support for the analytic and one-term results.
ReproductionSatisfied for the computational batch by fresh unchanged execution plus a structurally disjoint partition/recurrence route. The retained driver regenerates its outputs, checks actual script imports and compares all data. Noncomputational conclusions retain complete derivations and attacks.
Source and verdict fidelitySatisfied within the supplied extraction. Credits, exact external versions and source limits are preserved. Static proof reading is not described as a kernel check; unlisted archives and prior rulings are not represented as examined. The nine verdicts below cover only the frozen subject.

Reproduction

The retained package is self-contained for the checks, with the repository's already prepared Python environment. It requires no installation, synchronization, Lean, network, corpus scan, gate or ledger command. The independent program uses only the Python standard library. The unchanged author program additionally uses the supplied 17-file runtime closure.

From the directory containing this report, set REVIEW_SCRATCH to an absolute writable scratch directory and run the following. The output directory is explicitly selected; no result is written into the subject snapshot.

sh
test -n "$REVIEW_SCRATCH" &&
nice -n 10 env \
  -u VIRTUAL_ENV -u UV_PROJECT -u UV_PROJECT_ENVIRONMENT \
  -u UV_WORKING_DIR -u UV_NO_PROJECT -u PYTHONPATH \
  PYTHONDONTWRITEBYTECODE=1 \
  OMP_NUM_THREADS=1 OPENBLAS_NUM_THREADS=1 MKL_NUM_THREADS=1 \
  NUMEXPR_NUM_THREADS=1 VECLIB_MAXIMUM_THREADS=1 BLIS_NUM_THREADS=1 \
  uv run --no-sync python -B rerun.py --output "$REVIEW_SCRATCH"

The driver runs sequentially, using the interpreter selected by this command. For the author invocation it sets PYTHONPATH to the absolute subject/tools_runtime directory and invokes subject/finite/small_cases.py.txt as an actual script file, with --output under the selected scratch directory. It verifies the loaded tools source paths from that invocation's import trace. The original historical docstring command is left unchanged in the snapshot and is not the current path. The driver then runs finite/independent.py on finite/claims.json and on finite/negative_claims.json, the latter under Python -O.

Expected successful driver result: exit zero; all 28 count/witness rows equal; 17 supplied tools origins confirmed; the positive independent run exits zero and the three-case negative run exits one. The driver writes fresh author_results.json, independent_results.json, negative_results.json and verification.json plus disposable subprocess diagnostics into scratch. Ordinary runtime is under one minute on one thread; the bounded inputs here completed within that scope. A failure in a constituent run, comparison or import-origin obligation makes the driver exit nonzero. No cached success is an input to its decision.

For a direct independent run from the same directory:

sh
test -n "$REVIEW_SCRATCH" &&
nice -n 10 env \
  -u VIRTUAL_ENV -u UV_PROJECT -u UV_PROJECT_ENVIRONMENT \
  -u UV_WORKING_DIR -u UV_NO_PROJECT -u PYTHONPATH \
  PYTHONDONTWRITEBYTECODE=1 \
  OMP_NUM_THREADS=1 OPENBLAS_NUM_THREADS=1 MKL_NUM_THREADS=1 \
  NUMEXPR_NUM_THREADS=1 VECLIB_MAXIMUM_THREADS=1 BLIS_NUM_THREADS=1 \
  uv run --no-sync python -B finite/independent.py \
  --input finite/claims.json --output "$REVIEW_SCRATCH/direct.json"

The scratch directory must already exist for this direct invocation. Replacing the input by finite/negative_claims.json, adding Python's -O flag and choosing another output filename must return exit one, not zero. The full driver performs that control automatically. These instructions use package-relative inputs so moving the complete report directory does not alter a mathematical check.

Retained artifacts are the unchanged subject snapshot, the independent source, the two exact input files, the complete fresh author data, the independent counts/certificates and the failed-control counts/witnesses. In particular finite/author_results.json is the concrete fresh count/witness data, not a terminal success summary. The independent outputs retain endpoint AP inventories, partition polynomials and conditional witness counts, or the allowable recurrence seeds. The prose derivation is essential to interpreting the four-term recurrence computation.

Verdict and limitations

ConclusionMathematical verdict
Polynomial bound for 2, every integer k≥5k\geq5refutation-failed
Polynomial bound for k\sqrt{k}, every integer k≥2k\geq2refutation-failed
N(2,2)=3N(2,2)=3refutation-failed
N(3,2)=9N(3,2)=9refutation-failed
N(4,2)=13N(4,2)=13refutation-failed
Nonexistence of N(1,2)N(1,2)refutation-failed
Actual minimum N(1,1)=1N(1,1)=1refutation-failed
N(k,2)≤16kN(k,2)\leq16^k for every integer k≥2k\geq2refutation-failed
N(k,k)≤64kN(k,\sqrt{k})\leq64^k for every integer k≥1k\geq1refutation-failed

The frozen argument survived the stated attacks. No missing essential mathematical premise, counterexample or unfinished mathematical coverage obligation was found within the commissioned read set. This includes the complete finite Fourier/Fejér and wrapping chain, all model and minimum bridges, exact finite rerun and disjoint reproduction, and every base and exponential consequence.

The scope is mathematical proof inspection plus the specified exact finite computations. No Lean elaboration, native_decide execution, compiler trust audit or kernel replay was performed. The report does not establish fidelity of an unlisted source file, the complete archives, their license texts, any reported source build, or later changed bytes. The finite data says nothing about other parameter values without the displayed mathematical reductions. No optimality of the general bounds is asserted.

A distinct fresh grader must assess this unchanged report, its independence and its keeper evidence, preserving the premise order for the two consequences. This report awards no tier, problem status or acceptance.