9.5. Infinitude
Infinitely many irregular primes. The set
\{p:\mathbb{N} \mid p\text{ is prime and }p\text{ is not regular}\} is infinite.
Lean code for Theorem9.5.1●1 theorem
Associated Lean declarations
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theoremdefined in BernoulliRegular/IrregularPrimes/Infinitude.leancomplete
theorem BernoulliRegular.infinite_not_isRegularPrime : {p | ∃ (_ : Nat.Prime p), ¬IsRegularPrime p}.Infinite
theorem BernoulliRegular.infinite_not_isRegularPrime : {p | ∃ (_ : Nat.Prime p), ¬IsRegularPrime p}.Infinite
Infinitely many primes are not regular, by the Carlitz route.
Assume the set is finite, and let S be a finite set containing all of its
elements. By Theorem 9.4.1, there is a prime
p\notin S which is not regular. This contradicts the defining property of S.
Hence no finite set covers all irregular primes, so the set is infinite. The
finite-set-to-infinite conversion is the elementary lemma that no finite cover
implies infinitude infinite_of_forall_finite_set_not_cover.
The checked proof contains no bundled Kummer provider or side-condition package. The only source bridge into irregularity is Kummer's criterion, and the unbounded congruence used by Carlitz is the public theorem Theorem 9.1.1.