The prime-values conjecture for Drinfeld-module auxiliary polynomials

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Let AA be the coefficient ring and let

ϕ:A→A{τ}\phi:A\rightarrow A\{\tau\}

be a Drinfeld module. For each prime polynomial PP, let gP,ϕg_{P,\phi} denote the auxiliary polynomial associated with PP and ϕ\phi. Prime-values conjecture. There exist infinitely many prime polynomials PP such that gP,ϕg_{P,\phi} is prime. This conjecture is stated as the remaining assumption needed to prove that infinitely many values ϕP(a)\phi_P(a) are non-prime, or equivalently that infinitely many ϕ\phi-Mersenne numbers are not prime; the supplied text gives no resolution.

References

Primary source

Alexis Lucas, “Wieferich and Mersenne primes for function fields”, arXiv:2512.08060 (2025).

Progress summary

Refreshed
Open

The conjecture remains open in general, although it is known for the special Carlitz module.

The conjecture asks whether every Drinfeld module has infinitely many prime polynomials PP for which the associated auxiliary polynomial gP,ϕg_{P,\phi} is prime. It is used as the remaining assumption in a result on infinitely many non-prime Drinfeld-module Mersenne numbers.

Known results

  • For the Carlitz module, gP,ϕ=P−1g_{P,\phi}=P-1, and Hall’s theorem gives infinitely many prime polynomials PP for which both PP and P−1P-1 are prime.

December 2025 preprint

Alexis Lucas’s Wieferich and Mersenne primes for function fields states the conjecture and proves consequences assuming it, but reports no proof or counterexample for the general case.

Current status (as of September 2026): The conjecture remains open for general Drinfeld modules; it is known for the Carlitz module, and no proof or counterexample for the general statement has been reported.

Sources

Solutions 0

No solutions have been posted yet.