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Every Odd Number Greater Than 1 is the Sum of at Most 973 Primes

Proved
odd_sum_le_973_primes

by xuanji · Oct 3, 2026 · Mathlib 0df444a (Lean v4.33.1)

goldbachnumber-theoryschnirelmann-densitysieve-theory

Every odd natural number greater than 111 is a sum of at most 973973973 primes, with repetition allowed.

Precisely: for every n∈Nn \in \mathbb{N}n∈N with nnn odd and n>1n > 1n>1 there is a finite multiset sss of natural numbers such that

∣s∣≤973,every p∈s is prime,∑p∈sp=n.|s| \le 973, \qquad \text{every } p \in s \text{ is prime}, \qquad \sum_{p \in s} p = n.∣s∣≤973,every p∈s is prime,p∈s∑​p=n.

Here ∣s∣|s|∣s∣ counts elements with multiplicity, so the same prime may be used several times, and the order of the summands is irrelevant.

This is the campaign statement of Odd numbers as sums of primes with the value 973973973.

Formalization Note The representation is a Multiset ℕ; the bound is on Multiset.card, so repeated primes count separately.

Preamble
import Mathlib
Formal statement
theorem odd_sum_le_973_primes (n : ℕ) (hodd : Odd n) (hn : 1 < n) :
    ∃ s : Multiset ℕ, s.card ≤ 973 ∧ (∀ p ∈ s, Nat.Prime p) ∧ s.sum = n := by
  sorry
Source
AI-assisted explicit calculation (unpublished, October 2026): weighted fourth-moment / Hölder argument, sigma(A) >= 1/350, m = 243, K = 4m + 1 = 973; framework: P. Pollack, Not Always Buried Deep, Ch. 6 §6, pp. 196–201, https://www.pollack-math.net/NABDofficial.pdf
Read-back

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

Read-back of odd_sum_le_973_primes. Let nnn be any natural number n∈N={0,1,2,… }n \in \mathbb{N} = \{0, 1, 2, \dots\}n∈N={0,1,2,…} with two hypotheses:

  • nnn is odd, meaning n=2k+1n = 2k + 1n=2k+1 for some k∈Nk \in \mathbb{N}k∈N;
  • 1<n1 < n1<n, which is strict.

Together these say that nnn is an odd number with n≥3n \ge 3n≥3. Both hypotheses can be satisfied, for example by n=3,5,7,…n = 3, 5, 7, \dotsn=3,5,7,…. The cases n=0n = 0n=0 and n=1n = 1n=1 are excluded, and so are all even nnn.

The statement says that for every such nnn there exists a finite multiset sss of natural numbers satisfying all three of these conditions:

∣s∣≤973,every element p∈s is prime,∑p∈sp=n.|s| \le 973, \qquad \text{every element } p \in s \text{ is prime}, \qquad \sum_{p \in s} p = n .∣s∣≤973,every element p∈s is prime,p∈s∑​p=n.

Here are the terms and edge cases:

  • A multiset is an unordered finite collection in which an element may appear more than once.
  • ∣s∣|s|∣s∣ is the number of elements of sss counted with multiplicity. The bound is "at most 973" (≤\le≤), not "exactly 973".
  • The sum also counts each element with its multiplicity.
  • "Prime" is the usual notion for natural numbers: p≥2p \ge 2p≥2 and the only divisors of ppp are 111 and ppp.

So the conclusion says that nnn can be written as a sum of at most 973973973 primes, where repeats are allowed and order does not matter. Nothing requires the primes to be distinct, to be odd, or to be different from 222. Nothing requires the number of summands to be any particular value other than being at most 973973973; a single summand (s={n}s = \{n\}s={n} when nnn is prime) is allowed. The empty multiset has sum 000, so it can never be a witness, because n≥3n \ge 3n≥3. The statement only asserts that such an sss exists. It says nothing about sss being unique or how to construct it.

Human review
  • Endorsed by Shuze Chen · Oct 4, 2026

    Confirmed by the moderator at approval.

  • Endorsed by xuanji · Oct 4, 2026

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

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