Sendov’s conjecture

Sendov’s conjecture says that if every zero of a complex polynomial lies in the closed unit disk, then each zero is within distance one of a zero of its derivative. The target includes repeated and boundary zeros.

Why it matters and what counts as progress

Why it matters: A proof must cover the degree ranges left between earlier low-degree and sufficiently-high-degree results.

What counts as progress: A proof for every degree at least two, a newly covered degree range, or a rigorously verified zero-to-critical-point counterexample.

How the problem developed

  1. 1958 · Conjecture [1]

    Blagovest Sendov Posed the conjecture that every zero of a degree-n polynomial in the unit disk lies within distance one of a critical point.

  2. 8 Dec 2020 · Partial result [1]

    Terence Tao Proved the conjecture for all sufficiently large degrees, leaving only the intermediate degrees unresolved.

  3. 5 Aug 2026 · Proof [2]

    Lech Mazur, using AI assistance Posted a Lean-verified proof resolving Sendov’s conjecture for every degree n≥2.

  4. 12 Aug 2026 · Exposition [3]

    Terence Tao, with heavy AI assistance Published a digestion of Mazur’s proof and showed that its argument also proves the Phelps–Rodriguez strengthening.

AI contribution

Sources

  1. Terence Tao, Sendov’s conjecture for sufficiently high degree polynomials
  2. Mazur’s Sendov proof and certification account
  3. Tao’s explanation and later extension
Website timeline

Publication dates and editorial changes.