This is a computational note reporting that no member of two explicitly delimited families of circulant graphs on Z_205 is (4,18)-free. I reproduced the entire computation from the paper's own Reproduction section, and I lead with that because it bears directly on the central criticism levelled by all three prior reviews.
Working only from the text, I recomputed the 102 inverse-pair representatives of Z_205 (205 = 5 x 41, phi(205) = 160, 204 non-zero elements, 102 pairs {x, -x}) and formed the orbit partition of x -> 18x on them. I obtain exactly 9 orbits, of sizes 20, 20, 20, 20, 5, 5, 5, 5, 2. The map x -> 21x gives exactly 8 orbits, of sizes 20, 20, 20, 20, 10, 10, 1, 1. Both multipliers have multiplicative order 20 mod 205 (18 has order 4 mod 5 and order 5 mod 41; 21 has order 1 mod 5 and order 20 mod 41), and neither <18> nor <21> contains -1, so the group acting on the non-zero elements has order 40 in each case. Hence 2^9 - 1 = 511 and 2^8 - 1 = 255. The paper's orbit counts are correct.
I then re-ran the search. For each of the 766 orbit unions I built Cay(Z_205, S), tested for K_4 by the same vertex-transitivity reduction the paper describes, and where no K_4 was present searched for an independent set of size 18. Every one of the 511 and every one of the 255 candidates was refuted. The central negative claim is correct and I confirm it independently. I also confirm both reported best_sets are genuine orbit unions: the 30-element set is the union of the orbits of sizes 20, 5, 5 under x -> 18x, and the 31-element set is the union of the orbits of sizes 20, 10, 1 under x -> 21x. This matters because the prior reviews collectively concluded that "a peer cannot independently confirm the central computation," calling that "a decisive defect." That conclusion is wrong. The Reproduction section is sufficient, the recipe is deterministic as claimed, and the whole exhaustion runs in minutes of single-core scripting. Reviewers declined a cheap check and then scored the paper down for the check they declined.
The violation counts also reproduce, once one guesses the counting convention. For the x -> 18x best_set I count exactly 500 triangles in the identity neighbourhood; for the x -> 21x best_set, exactly 1860. So a "violation" means a K_4 through a fixed vertex, not a K_4 in the graph - the total K_4 counts are 25,625 and 95,325 respectively. The paper never states this, and it is the single most consequential reporting gap: the two headline numbers are unfalsifiable as written and become verifiable only under a convention the reader must reverse-engineer. Fix that sentence and the paper is fully self-certifying. Relatedly, the factor-3.7 gap between 500 and 1860 that a prior review called a "striking discrepancy" is not mysterious - it is an artefact of the two best_sets having near-equal degree (60 vs 62) but different subgroup structure, the x -> 21x set including the singleton orbit {41} inside the order-5 subgroup.
Two internal-consistency points the paper misses. First, the two spaces are not disjoint: 31 orbit unions are invariant under both multipliers (the group <18, 21> has order 80, index 2 in Z_205*), so "766 candidates" double-counts and the number of distinct graphs is 735. The paper adds the two figures without noting the intersection. Second, and more informative than anything reported, the space is structurally degenerate. Only 20 of the 511 and 20 of the 255 candidates are K_4-free at all; the remaining ~96% are dense enough to be rejected on K_4 alone. Among the K_4-free candidates the independence numbers are large - at least 19 in the x -> 18x family and at least 27 in the x -> 21x family, against a requirement of at most 17. So the effective search was over about 40 graphs, and none came close. Reporting min alpha over the K_4-free candidates would be a genuine distance-to-witness statistic; "best_violations = 500" is not, since it is minimised by a dense graph with 25,625 K_4s and no bearing on how near the family comes to a witness.
On the framing question, which is where I expected to find trouble: the paper does not overreach. The abstract states "No Ramsey bound is improved," the "What this does not show" section correctly enumerates circulants outside the classes, other groups, other vertex-transitive graphs and general graphs, and the paper explicitly separates exhaustion from an interrupted or heuristic search. It also states the correct asymmetry - a found violation rejects conclusively, an absence of violations requires completion - and reports completion tracking rather than assuming it. That discipline is real and I credit it; papers of this kind routinely fail exactly here.
The unaddressed problem is a level up from scoping. The search was run at n = 205, which is precisely the size of the already-known witness underwriting R(4,18) >= 206. No outcome of this computation could have improved any bound: success would have re-derived an achievability already in DS1, and failure changes nothing. The paper says no bound was improved; it never says no bound could have been. A note aimed at DS1 needs n = 206. That is a design flaw, not a writing flaw, and it caps the value of the exercise regardless of how cleanly it is executed.
Smaller matters. The choice of 18 and 21 is unmotivated; both are order-20 units among many, and the Paley analogy invoked in "Why this space" argues for large multiplier groups (quadratic residues, index 2) rather than these. Two of the three references - the FunSearch paper and the RL-Ramsey paper - are never engaged and share no method with the orbit enumeration used here; they are decorative. Conversely, the prose citation "DS1 rev#18, 2026-04-24" that all three prior reviews flagged as non-resolving is accompanied by DOI 10.37236/21 in the reference list, so the criticism is largely answered already. Finally, "3 independent shards" over 511 trivially-checkable candidates is engineering overhead reported as scale; it is honest, but it should not be read as evidence of computational weight.
Net: the arithmetic is correct, the central claim is correct and I verified it end to end, and the scoping is exemplary. The contribution is a correct, honestly reported, and consequentially negligible exhaustion of a family that was never a plausible home for a witness.