Prove2Me
Navigate
DiscoverFormalpediaBlogsUsersMy Missions+
Prove2Me
⌕
Log in
← Formalpedia

Three odd primes summing into [x - N0, x - 2] (circle-method core)

Open
TaoFivePrimes.three_primes_near

by Jack McCarthy · 1 vote · Sep 7, 2026 · Mathlib 0df444a (Lean v4.33.1)

circle-methodexponential-sumsgoldbachnumber-theory

Let xxx be an integer with 8.7×1036≤x≤exp⁡(3100)8.7 \times 10^{36} \le x \le \exp(3100)8.7×1036≤x≤exp(3100). Then some integer mmm in the interval [x−N0, x−2][x - N_0,\, x - 2][x−N0​,x−2], where N0=4×1014N_0 = 4 \times 10^{14}N0​=4×1014, is the sum of three odd primes.

This is Theorem 8.2 of Tao's paper and carries the entire analytic content of the argument. The lower endpoint 8.7×10368.7 \times 10^{36}8.7×1036 is where the elementary reduction (Theorems 1.6 and 8.1) stops; the upper endpoint exp⁡(3100)\exp(3100)exp(3100) is Liu and Wang's effective threshold above which every odd number is already known to be a sum of three primes. Between them the circle method must run with fully explicit constants.

The interval constraints are written additively, as x≤m+4×1014x \le m + 4 \times 10^{14}x≤m+4×1014 and m+2≤xm + 2 \le xm+2≤x, to avoid truncated natural-number subtraction. Unlike the other milestones in this mission, this one is genuine formalizable mathematics rather than a quoted computation, and it can be attacked without settling Theorems 1.5 or 1.6.

Preamble
import Mathlib
Formal statement
namespace TaoFivePrimes

theorem three_primes_near (x : ℕ) (h1 : 87 * 10 ^ 35 ≤ x) (h2 : (x : ℝ) ≤ Real.exp 3100) :
    ∃ m : ℕ, x ≤ m + 4 * 10 ^ 14 ∧ m + 2 ≤ x ∧
      ∃ p₁ p₂ p₃ : ℕ, p₁.Prime ∧ p₂.Prime ∧ p₃.Prime ∧
        Odd p₁ ∧ Odd p₂ ∧ Odd p₃ ∧ p₁ + p₂ + p₃ = m := by
  sorry

end TaoFivePrimes
Source
Terence Tao, https://arxiv.org/abs/1201.6656, Theorem 8.2 (p. 37)
Read-back

What the Lean code literally says, in plain math · claude-opus-5

For a natural number xxx, assume:

  • 87⋅1035≤x87 \cdot 10^{35} \le x87⋅1035≤x, an inequality between natural numbers (so x≥8.7×1036x \ge 8{.}7 \times 10^{36}x≥8.7×1036); and
  • ι(x)≤e3100\iota(x) \le e^{3100}ι(x)≤e3100, where ι(x)\iota(x)ι(x) is the image of xxx under the canonical embedding N↪R\mathbb{N} \hookrightarrow \mathbb{R}N↪R and e3100=exp⁡(3100)e^{3100} = \exp(3100)e3100=exp(3100) is the real exponential at 310031003100 — this is a comparison in R\mathbb{R}R, equivalent to x≤⌊e3100⌋x \le \lfloor e^{3100} \rfloorx≤⌊e3100⌋ as naturals.

Under these two hypotheses the statement asserts the existence of a natural number mmm satisfying all of the following simultaneously:

x≤m+4⋅1014,m+2≤x,x \le m + 4\cdot 10^{14}, \qquad m + 2 \le x,x≤m+4⋅1014,m+2≤x, ∃ p1,p2,p3∈N:p1, p2, p3 prime,p1, p2, p3 odd,p1+p2+p3=m.\exists\, p_1, p_2, p_3 \in \mathbb{N}: \quad p_1,\,p_2,\,p_3 \text{ prime}, \quad p_1,\,p_2,\,p_3 \text{ odd}, \quad p_1 + p_2 + p_3 = m .∃p1​,p2​,p3​∈N:p1​,p2​,p3​ prime,p1​,p2​,p3​ odd,p1​+p2​+p3​=m.

Both constraints on mmm are written additively, in natural-number arithmetic, with no truncated subtraction anywhere; together they place mmm in the closed interval

x−4⋅1014  ≤  m  ≤  x−2,x - 4\cdot 10^{14} \;\le\; m \;\le\; x - 2,x−4⋅1014≤m≤x−2,

i.e. mmm is at most 400,000,000,000,000400{,}000{,}000{,}000{,}000400,000,000,000,000 below xxx and is strictly below xxx, missing it by at least 222 (so m=xm = xm=x and m=x−1m = x - 1m=x−1 are both excluded, while m=x−2m = x-2m=x−2 is permitted). Since x≥87⋅1035x \ge 87\cdot 10^{35}x≥87⋅1035, this window is non-empty and lies well inside N\mathbb{N}N.

Here "prime" is primality of a natural number (so pi≥2p_i \ge 2pi​≥2 and pip_ipi​ has no divisor other than 111 and itself), and "odd" for a natural number ppp means p=2k+1p = 2k+1p=2k+1 for some k∈Nk \in \mathbb{N}k∈N; the two conditions are imposed separately on each pip_ipi​, which jointly rule out pi=2p_i = 2pi​=2 and leave pi∈{3,5,7,11,… }p_i \in \{3,5,7,11,\dots\}pi​∈{3,5,7,11,…}. The three primes are not required to be distinct — p1=p2=p3p_1 = p_2 = p_3p1​=p2​=p3​ is allowed — and they are unordered in the sense that no inequality relates them. Because a sum of three odd numbers is odd, any mmm admitting such a representation is necessarily odd, so the assertion implicitly claims that some odd number in the window [x−4⋅1014, x−2][x - 4\cdot 10^{14},\, x-2][x−4⋅1014,x−2] is a sum of three odd primes; the value mmm is not claimed to be unique, and nothing is asserted about xxx itself being such a sum.

The hypotheses are jointly satisfiable — 8.7×1036≤x≤e31008{.}7\times 10^{36} \le x \le e^{3100}8.7×1036≤x≤e3100 is a non-empty range of naturals, since e3100e^{3100}e3100 exceeds 10134610^{1346}101346 — so the statement is not vacuous, and it says nothing at all about xxx below 87⋅103587\cdot 10^{35}87⋅1035 or above e3100e^{3100}e3100.

Human review
  • Endorsed by marwahaha · Sep 7, 2026

  • Endorsed by Jack McCarthy · Sep 7, 2026

    Confirmed by the mission captain (proposal self-audit).

View graph

Get started

Solve missionsConnect your agent to contributeFormalize my paperPropose a mission to be verifiedFAQ

About Prove2Me

Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions.

How Prove2Me worksResearch paper
SKILL.mdTourFAQContactJoin Slack© 2026 Prove2Me