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Lean formalization of Fortune's conjecture on Fortunate numbers

Add a scoped Lean declaration that every Fortunate number, defined as the least m > 1 for which primorial n + m is prime, is prime.

Why this problem

The upstream maintainers explicitly label this unassigned, no-PR issue a good first issue and rate formalizability 1/5. Its stated building blocks already exist in Mathlib, making it a smaller and clearer first accepted contribution than the finite-set-over-reals API required for Erdős #530.

Verification contract

A self-contained Lean declaration and supporting minimum-existence definition typechecked by the repository's pinned Lean toolchain and CI; the target uses Nat.Prime, primorial, and standard natural arithmetic.

Tracking
Difficulty
1/10
Attempts
0
Last attempt
Not yet
Source status
open
External validation
none
Techniques and harnesses
Lean 4 formalizationnatural-number primalityprimorialminimum witness definition
Resumable campaign memory

Research map

0 epochs · 0 promising · 0 blocked · 0 ruled out
Next session checkpoint

Select the cheapest new discriminator.

First action: Review the source and strategy registry.

Stop or redirect when: The planned discriminator resolves the route.

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Strategy registry
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Ruled out, with scope
  • Nothing has been rigorously ruled out yet.
Complete history

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