arXiv:2604.18991v2

Handling some Diophantine equation via Euclidean algorithm and its application to purely exponential equations

Takafumi Miyazaki, Reese Scott, Robert Styer

math.NT11D6111D4511J8611D4111J87

Abstract

In this paper, we use a variety of classical and new research methods for ternary exponential Diophantine equations and extensive use of computer calculations to study the conjecture of R. Scott and R. Styer which asserts that for any fixed relatively prime positive integers a,ba,b and cc all greater than 1 there is at most one solution to the equation ax+by=cza^x+b^y=c^z in positive integers x,yx,y and zz, except for listed specific cases. Precisely, we confirm that for any fixed prime cc of the form 2r3+12^r \cdot 3 +1 with some positive integer rr the conjecture holds true, except for only finitely many cases all of which can be effectively determined. Most importantly we prove the conjecture to be true whenever c=7,13c = 7, 13, or 9797, giving another proof of the result of T. Miyazaki and I. Pink for c=13c=13. We also contribute to the estimation of the number of positive integer solutions (x,y)(x,y) to the equation axby=ca^x-b^y=c for any fixed positive integers a,ba,b and cc with both aa and bb greater than 1. Further, based on a key idea in the proofs of the above results, we present a new application of the Euclidean algorithm for polynomials to the polynomial-exponential Diophantine equation XmXn=qy1qy2 X^m - X^n = q^{y_1} - q^{y_2} in positive integers X,y1X, y_1 and y2y_2, where mm and nn are given positive integers with m>nm>n, and qq is a given prime.

AI-generated audit

Audit summary

Audited against arXiv v2

Not a correctness certificate. A “Correct” result may include yellow typos or minor formal corrections that do not affect substantive soundness. It means this audit found no unresolved substantive error under the stated criteria; it does not replace expert scrutiny or formal verification.

Current report

Detailed mathematical audit

Generated August 15, 2026
01Statements4 reported findingsContains unsupported statements

The effective-finiteness theorem and the Euclidean-algorithm congruence are supported. No counterexample was found to the two classification theorems, but their decisive computer calculations are not supplied in a reproducible form, so those conclusions are not able to be verified from the paper and cited sources.

Theorem 1Correct

Effective finiteness for fixed primes c=32r+1c=3\cdot2^r+1

Pages 3 and 7–11 · Theorem 1 and Section 5 · arXiv:2604.18991v2

The cited reductions leave only E=3E=3 and, outside an effectively bounded set, the system a+b=cza+b=c^z, a+bY=cZa+b^Y=c^Z with bounded Y4(mod6)Y\equiv4\pmod 6. Lemmas 5.9–5.12 give bcczb\gg_c c^z, whereas Lemma 5.8 and bY<cZb^Y<c^Z give b<c(Y1)z/Yb<c^{(Y-1)z/Y}. Hence cz/Yc1c^{z/Y}\ll_c1; bounded YY makes zz effectively bounded, and then a,ba,b are effectively bounded. This proves exactly the claimed effective finiteness.

Theorem 2Not able to verify

Classification for c{7,13,97}c\in\{7,13,97\}

Pages 4 and 13–35 · Theorem 2 and Sections 7–9 · arXiv:2604.18991v2

No counterexample was found. The c=13c=13 case is independently covered by the earlier result that the paper explicitly cites. For c=7c=7 and c=97c=97, however, the exclusions ultimately depend on large finite searches whose complete inputs, executable code, and output certificates are not provided. The displayed pseudocode in Section 8.4 is an outline rather than a reproducible implementation, and decisive computed claims such as Lemma 9.7 and the final brute-force checks are stated without certificates. The available material is therefore insufficient to verify the full three-value classification.

Theorem 3Not able to verify

Pillai-equation classification for the listed 24 primes

Pages 4 and 35–36 · Theorem 3, Tables 1–2, and Section 10 · arXiv:2604.18991v2

No counterexample was found. The paper reports that variants of earlier algorithms were run for every listed value of rr, including about 52 hours of computation for the second stage, but supplies only summary tables and no complete algorithm, code, case log, or independently checkable certificate. Since these searches eliminate all remaining cases and are essential to the universal conclusion, the theorem cannot be verified from the supplied record.

Proposition 11.1Correct

Congruence obtained from the polynomial Euclidean algorithm

Pages 37–41 · Proposition 11.1 and Lemmas 11.1–11.3 · arXiv:2604.18991v2

Factoring XmXnX^m-X^n with mn=ENm-n=EN and applying the lifting-the-exponent identity gives Equations (11.3)–(11.4), including y2>ey_2>e. The Bézout identity (11.2), evaluated at XX and combined with those valuations, yields the claimed congruence modulo qκq^\kappa. The two alternatives defining κ\kappa agree with the lower bounds for y1y_1 proved in Lemma 11.3.

02Proofs5 reported findingsContains unverified proofs

The proof of effective finiteness and the Euclidean-algorithm argument are complete. The proofs of the two explicit classification theorems omit the reproducible computational evidence needed to check their exhaustive searches; no mathematical contradiction in those conclusions was established.

Theorem 1Correct and complete

Reduction and effective-boundedness argument

Pages 7–11 · Lemmas 5.1–5.12 and proof of Theorem 1 · arXiv:2604.18991v2

The congruence and valuation steps preserve the required coprimality hypotheses, and the Euclidean identity in Lemma 5.11 gives a genuine integer divisibility. Together with the cited effective bounds, the final comparison bounds zz, then aa and bb, by effectively computable constants depending only on fixed cc. No case used in the reduction is lost.

Theorem 2, case $c=7$Incomplete as written

The exhaustive sieves are not reproducible from the displayed outline

Pages 16–29 · Sections 7.2 and 8.4 · arXiv:2604.18991v2

The argument requires exhaustive searches over large, dynamically computed bounds. Section 7.2 describes a multistage procedure and Section 8.4 prints high-level pseudocode, but operations such as the valuation sieves and the final power test are not specified as executable code and no output certificate is included. Repeating the claimed searches, rather than filling a routine technical detail, is necessary to exclude the remaining solutions. A repair would publish the exact Magma source, version, inputs, and auditable outputs or provide independently checkable certificates.

Theorem 2, cases $c=13,97$Incomplete as written

Decisive computed bounds and terminal checks lack certificates

Pages 29–35 · Section 9, especially Lemma 9.7 and proof of Theorem 2 · arXiv:2604.18991v2

Lemma 9.7 is obtained by checking every permitted ZZ on a computer, and the c=97c=97 proof then invokes further computer checks and a final brute-force computation. The manuscript does not provide code or output certificates for these steps. This is a verification limitation, not evidence that a computed bound or the theorem is false.

Theorem 3Incomplete as written

The 24-parameter computation is summarized but not specified

Pages 35–36 · Section 10 and Tables 1–2 · arXiv:2604.18991v2

The proof says that almost the same algorithms as in earlier sections were performed for the listed values of rr and reports aggregate running times. That description does not uniquely determine all computations, and the tables record intermediate bounds rather than certificates that every terminal case was rejected. Publishing a complete implementation and verifiable logs would address this audit finding.

Proposition 11.1Correct and complete

Valuation and Bézout-identity proof

Pages 37–41 · Equations (11.1)–(11.11) · arXiv:2604.18991v2

The proof separates the two signs allowed by the generalized order, uses oddness of NN to force XE1(modq)X^E\equiv1\pmod q, and applies the standard odd-prime lifting-the-exponent formula to IE,N(X)I_{E,N}(X). Clearing denominators in the polynomial Bézout identity and reducing at the exact modulus supplied by Lemma 11.3 yields the stated result without an omitted case.

03Novelty0 reported findingsNo non-novelty findings

No non-novelty findings.

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Paper
arXiv:2604.18991v2
Authors listed
Takafumi Miyazaki, Reese Scott, Robert Styer
Audit date
August 15, 2026
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