Codex proves two arithmetic-function conjectures in Lean

Lean proofs establish Dimitrov’s Conjectures 1 and 3, the stated rational lower bounds involving Euler’s totient φ(n), Dedekind’s ψ(n) and σ(n), for every integer k≥1 and n≥2. Equality in each bound holds exactly when n is prime.

Sources for this record

What was already known

Dimitrov posed the full-range inequalities and proved their k=1 cases; the source discusses k=2 and k=3 but not full-range proofs.

AI involvement AI-led

Mazur asked Codex to find and attempt recent open problems. The project credits Codex with selecting these targets, finding the reductions and writing the Lean proofs; Mazur directed and maintained the work.

Codex selected both conjectures and supplied their substantive mathematical reductions and Lean proofs under Mazur’s direction.

Importance Modest

The proofs extend two stated inequalities to all parameters and identify their equality cases.

Limitations

The other conjectures in Dimitrov’s paper are outside this result. Historical first-proof priority has not been independently confirmed.

Technical verification Formal (Lean 4.32.0/Mathlib, Comparator and NanoDa)

The cited repository reports a complete Lean/Mathlib proof of both full-range inequalities and equality cases, with no proof-library sorry or custom axiom. Its workflow reports exact Comparator matching, kernel and NanoDa checks; those are source-reported, not rerun here.

Formal checking

Lean build and trust-zero check, statement comparison, axiom audit and independent proof replay

Checker
Lean kernel, Comparator and NanoDa in Mazur’s reported workflow
Scope
Conjectures 1 and 3 for every k ≥ 1, n ≥ 2, plus equality iff n is prime
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Few

No human explanation of the central full-range reductions or completed human proof review is documented. Mazur’s project decisions do not establish mathematical understanding; Few records the missing evidence.

Correction and publication history

2026-10-18 · publication

The proofs extend two stated inequalities to all parameters and identify their equality cases.

Read this published revision