Preprint

Preprint offers conditional test for large-exponent Fermat solutions

A conditional analysis excludes relevant solutions at sufficiently large prime exponents in selected number fields and identifies an imaginary quadratic family with relative density 5/6.

A version 1 arXiv preprint dated 28 Aug 2026 presents a conditional route for excluding relevant, non-trivial solutions of a generalized Fermat equation once the prime exponent is sufficiently large. The result concerns the paper's designated class W_K,P and depends on two stated conjectures as well as a bound on valuations attached to an S_K'-unit equation. It is therefore not an unconditional claim that such equations have no solutions over every number field.

The underlying question is whether an equation in which three coefficient-weighted pth powers add to zero can be ruled out over an arbitrary number field K. A, B and C are nonzero elements of the ring of integers, and the prime exponent is at least 3. This is a theoretical study of number fields, coefficients, prime ideals, elliptic curves, Galois representations, S-unit equations and algebraic solution sets, not an empirical study with participants or a dataset.

The proof starts with an elliptic curve

To test that question, the paper uses the modular method. It attaches a Frey elliptic curve to a putative solution, studies local behavior, the Serre conductor and the mod-p Galois representation, then applies conjectural modularity and Eichler-Shimura machinery.

For p at least 5, under the stated condition on primes above p, the Frey curve is described as minimal and semistable at primes outside S_K'. The paper also states that p divides the valuation of its discriminant at those primes, while the residual representation has cyclotomic determinant, is finite flat above p, and has conductor supported on S_K'.

For sufficiently large p, the modular argument supplies an auxiliary elliptic curve, called E'. It has good reduction away from S_K', all of its 2-torsion points are defined over K, its residual Galois representation is isomorphic to the Frey curve's, and it has potentially multiplicative reduction at P.

From curves to a unit equation

That comparison turns the putative solution into a unit equation. The proof obtains two S_K'-units, called lambda and mu, whose sum is 1, then examines their valuations at a fixed prime ideal P.

The theorem requires every associated S_K'-unit solution to obey a bound: the larger absolute value of the valuations of lambda and mu at P must be no more than four times the valuation of 2 at P. The proof says both valuation cases lead to a contradiction, so no solution in W_K,P remains for every sufficiently large prime exponent.

A concrete imaginary quadratic family

One application focuses on imaginary quadratic fields formed from squarefree integers d at least 5, with negative d not congruent to 1 modulo 8. The coefficients are restricted to signed powers of 2 with nonnegative exponents. Under the paper's conjectural assumptions and the condition α_Pβ_Pγ_P ≠ 0, the result conditionally rules out solutions once the prime exponent is sufficiently large.

Within that setting, the proof gives an explicit list of the only displayed relevant S_K'-unit pairs: (2, -1), (-1, 2) and (1/2, 1/2).

The associated family of squarefree integers has relative density 5/6 among squarefree positive integers. This is a statement about the share of a specified arithmetic family within the squarefree integers, not an empirical effect estimate.

A result with clear boundaries

The scope is narrower than a general solution to the equation. The arbitrary-number-field result concerns the theorem's designated non-trivial solution class W_K,P at sufficiently large prime exponents, and the stated theorem requires α_Pβ_Pγ_P ≠ 0. It does not cover small prime exponents, solutions outside W_K,P or the cases excluded by that nonzero condition.

The preprint does not give a numerical cutoff for “sufficiently large.” The arbitrary-number-field conclusion remains tied to the two stated conjectures and to a valuation bound applying to every associated S_K'-unit solution.

Within those boundaries, the paper combines the modular method, an auxiliary-curve construction and a valuation contradiction to produce a conditional criterion for excluding large-exponent solutions. Its imaginary quadratic calculation adds an explicit unit list and a relative-density result, giving the abstract argument a clearly defined arithmetic family.

Paper data and sources

Original title: Generalized Fermat equation over number fields
Authors: Satyabrat Sahoo
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-28
DOI: Not available
Original paper · Full text

Versions and corrections

  1. Published automatically after legal-source, freshness, evidence, and independent-verification gates passed.