OAI/NumberTheory/DukePrimeDegree/Dynamics/SynchronizedReturns.lean

Synchronized compact shearing pairs with equal leaves

The four recurrence windows produce the small central portions of both leaf annuli at one common diagonal time. On the regular set, the measurable kernel is the intrinsic leaf. The annular selection then avoids the leafwise exceptional sets for rebasing, so both compact return pairs have equal intrinsic leaves.