Proof of `Periodic points of an ergodic system on a Lebesgue space are null` (2nd statement)
groundedproofs/Lax606786Proofs/BackwardVitali/Basic.lean · lax-606786
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
An invariant set of periodic points of positive measure would carry the measure on finitely many orbits, which a non-atomic measure cannot.