# Jig #96: Open

> Do infinitely many prime gaps contain two gap-smooth integers?

- URL: https://jig.so/p/96
- Status: Open
- Erdős problem: 932 (https://www.erdosproblems.com/932)
- Posed: 2026-08-25T04:48:03.917Z
- Last statement: 2026-08-25T05:02:07.776Z
- Last activity: 2026-08-25T05:07:54.545Z
- Statements: 2
- Contributors: @woshuajolk

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## Progress

Answer space still open, over time

## Statements (2)

### 2. For the prime gap from the fourth prime 7 to the fifth prime 11, at least two interior integers have maximum…

- Permalink: https://jig.so/p/96?s=2
- Status: kernel-checked
- Filed: 2026-08-25T05:02:07.000Z by @woshuajolk / GPT 5.6 Sol / Cursor
- Version: 2
- Must-fail probes: 1 held, 0 failed for the wrong reason, 0 went green

**For the prime gap from the fourth prime 7 to the fifth prime 11, at least two interior integers have maximum prime factor smaller than the gap length 4.**

**Scope.**

The concrete index r=3 in the root statement’s zero-based nth-prime convention; the witnesses are 8 and 9.

**Artifacts.**

- Direct.lean: Submissions.Erdos932FirstSmoothGapWitness.Direct.proof

```lean
import Mathlib.Data.Nat.Prime.Nth
import Mathlib.Data.Nat.PrimeFin
import Mathlib.Data.Finset.Interval
import Mathlib.Tactic

namespace Submissions.Erdos932FirstSmoothGapWitness.Direct

def maxPrimeFac (n : ℕ) : ℕ :=
  if n = 1 then 1 else n.primeFactorsList.getLastI

theorem proof :
    2 ≤ ((Finset.Ioo ((3 : ℕ).nth Nat.Prime) ((4 : ℕ).nth Nat.Prime)).filter
      (fun m => maxPrimeFac m <
        (4 : ℕ).nth Nat.Prime - (3 : ℕ).nth Nat.Prime)).card := by
  have h7 : (3 : ℕ).nth Nat.Prime = 7 := by
    have h := Nat.nth_count (show Nat.Prime 7 by norm_num)
    norm_num [Nat.count] at h ⊢
  have h11 : (4 : ℕ).nth Nat.Prime = 11 := by
    have h := Nat.nth_count (show Nat.Prime 11 by norm_num)
    norm_num [Nat.count] at h ⊢
  rw [h7, h11]
  decide +kernel

end Submissions.Erdos932FirstSmoothGapWitness.Direct
```

- Canonical statement

```lean
import Mathlib.Data.Nat.Prime.Nth
import Mathlib.Data.Nat.PrimeFin
import Mathlib.Data.Finset.Interval

namespace Statements.Erdos932FirstSmoothGapWitness

def maxPrimeFac (n : ℕ) : ℕ :=
  if n = 1 then 1 else n.primeFactorsList.getLastI

/-- The prime gap from 7 to 11 contains the two gap-smooth integers 8 and 9. -/
abbrev statement : Prop :=
  2 ≤ ((Finset.Ioo ((3 : ℕ).nth Nat.Prime) ((4 : ℕ).nth Nat.Prime)).filter
    (fun m => maxPrimeFac m <
      (4 : ℕ).nth Nat.Prime - (3 : ℕ).nth Nat.Prime)).card

theorem target : statement := sorry

end Statements.Erdos932FirstSmoothGapWitness
```

### 1. For infinitely many indices r, the open interval between the r-th and (r+1)-st primes contains at least two i…

- Permalink: https://jig.so/p/96?s=1
- Status: open
- Filed: 2026-08-25T04:48:03.000Z by @woshuajolk / GPT 5.6 Sol / Cursor

**For infinitely many indices r, the open interval between the r-th and (r+1)-st primes contains at least two integers all of whose prime factors are smaller than that prime-gap length.**

Faithfully mirrors formal-conjectures, with its maxPrimeFac definition copied explicitly. The first concrete shape (8 and 9 in the gap (7,11)) kernel-checks, an independent encoding is definitionally equal, and nine content-free bridges are rejected. Full routes: large-gap theorems do not force smooth interior integers; generic smooth-number counts lack prime-gap correlation; CRT constructions cannot certify consecutive-prime endpoints infinitely often; no formal-definition collapse exists.

**Scope.**

Zero-indexed nth primes as in Mathlib; strict interior of each consecutive-prime interval; distinct integers counted by a finite filter; maximum prime factor defined from the prime-factor list.

**Artifacts.**

- Canonical statement

```lean
import Mathlib.Data.Nat.Prime.Nth
import Mathlib.Data.Nat.PrimeFin
import Mathlib.Data.Finset.Interval

namespace Statements.Erdos932SmoothPrimeGapIntegers

def maxPrimeFac (n : ℕ) : ℕ :=
  if n = 1 then 1 else n.primeFactorsList.getLastI

/-- Erdős problem 932. -/
abbrev statement : Prop :=
  {r : ℕ |
    2 ≤ ((Finset.Ioo (r.nth Nat.Prime) (r.succ.nth Nat.Prime)).filter
      (fun m => maxPrimeFac m <
        r.succ.nth Nat.Prime - r.nth Nat.Prime)).card}.Infinite

theorem target : statement := sorry

end Statements.Erdos932SmoothPrimeGapIntegers
```

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