Theorem · version 2

Strict distance and the equality exception

Statement

Under Sendov’s assumptions, every zero a has a critical point ζ with ∣ζ−a∣<1|\zeta-a|<1, unless |a| = 1 and p(z)=c(zn−an)p(z)=c(z^n-a^n) for a nonzero complex constant c.

Assumptions

  • Degree n ≥ 2.
  • All zeros of p are in the closed unit disk.

Scope

The stronger Phelps–Rodriguez conclusion includes its precise exceptional family; it is not a second formulation of the same distance bound.

Distance
Strictly less than one
Exceptions
A boundary root |a| = 1 with p(z) = c(zⁿ − aⁿ), c ≠ 0

Evidence

Formal proofs

Connections

In this problem · publication v2 · Selected context

Sendov’s conjecture →

Different statement · related variant · Proved

Relationship not independently reviewed. This concerns its use in this problem.

In this problem · publication v8

Sendov’s conjecture →

Different statement · related variant · Proved

Relationship not independently reviewed. This concerns its use in this problem.

Sources

A digestion of the proof of Sendov’s conjecture →

Terence Tao · Project documentation · Publication date Aug 12, 2026

Public manuscript or exposition; publication does not imply independent OpenMath review.

Revision & attribution

Source revision: 2026-08-12. Observed Oct 13, 2026.

Terence Tao performed mathematical digestion and simplification with substantial AI assistance; this descends from Mazur’s argument and is not an independent discovery route.

Source updated Aug 12, 2026.

Sendov and Phelps–Rodriguez in Lean →

Terence Tao · teorth/sendov project · Project documentation · Publication date Aug 19, 2026

Public formal source; build and independent mathematical review are separate checks.

Revision & attribution

Source revision: 1ddea92d89f951a0a7cbbffa6c267cf7e6640b1d. Observed Oct 13, 2026.

The project reports Claude Opus 5 wrote essentially all Lean source under the author’s direction and review; this is a second formalization of the same mathematical argument.

Source updated Aug 19, 2026.

Sendov and Phelps–Rodriguez in Lean — pinned source: 1ddea92d89f951a0a7cbbffa6c267cf7e6640b1d.

History

Statement versions

Statement versions and problem publication versions are separate. A new publication can update context or sources while retaining the same statement.

Assessment history · 2

Assessments retained in these publication records. Earlier statement versions retain their own source histories.

Record details
Claim ID
claim-sendov-phelps-rodriguez
Statement version
2
SHA-256
c54a1c916ffc6f43f1f15e8f68d181b259407d69f264c03f9945d95477e945ea

Publication records