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Source labels openChecked July 26, 2026

Erdős ProblemsNumber theory

Erdős Problem 1055

A prime pp is in class 11 if the only prime divisors of p+1p+1 are 22 or 33. In general, a prime pp is in class rr if every prime factor of p+1p+1 is in some class r1\leq r-1, with equality for at least one prime factor. Are there infinitely many primes...

Mathematical statement

A prime pp is in class 11 if the only prime divisors of p+1p+1 are 22 or 33. In general, a prime pp is in class rr if every prime factor of p+1p+1 is in some class r1\leq r-1, with equality for at least one prime factor. Are there infinitely many primes in each class?

Statement source: Erdős Problems statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

erdos_1055

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem erdos_1055 (r) : {p | p.Prime  IsOfClass r p}.Infinite := by  sorry
Statement source
Formal Conjectures
Lean version
v4.27.0
Placeholder
Present; no proof artifact
Source evidence
Pinned source index
Fidelity review
Community formulation

References