Erdős problem 16
Is the set of odd integers not of the form the union of an infinite arithmetic progression and a set of density ?
Sources
FormalConjectures/ErdosProblems/
16.lean
Retained formal statement
Is the set of odd integers not of the form the union of an infinite arithmetic progression and a set of density ?
Erdős called this conjecture "rather silly".
Chen [Ch23] has proved the answer is no.
This was formalized in Lean by Chin using Aristotle.
False ↔ ∃ A B, Erdos16.Erdos16Set = A ∪ B ∧ (∃ a, ∃ d > 0, A = {x | ∃ m, x = a + m * d}) ∧ Erdos16.density_zero B