OAI/Geometry/RCD/Coordinates/Proper.lean
3 declarations, 0 contain sorry, 0 declared as axioms
Properness from the actual curvature-dimension volume bound
The existing FullCD.ball_ratio theorem bounds the mass of every small
ball centered in a bounded region from below. Disjoint small balls therefore
bound every separated set. The resulting finite nets prove total boundedness;
completeness then gives properness. No compactness hypothesis is added.
- theorem
OAI.RegularPointCoordinates.separated_encard_le_of_finset_boundline 23 - theorem
OAI.RegularPointCoordinates.NoncollapsedRCD.totallyBounded_closedBallline 45Source documentation
Every bounded ball is totally bounded, directly from CD volume comparison.
theorem NoncollapsedRCD.totallyBounded_closedBall {K : ℝ} {n : ℕ} (hX : NoncollapsedRCD K n X) (hn : 2 ≤ n) (p : X) (R : ℝ) : TotallyBounded (closedBall p R) := by … - theorem
OAI.RegularPointCoordinates.NoncollapsedRCD.properSpaceline 116Source documentation
The proper-space assumption of the conditional chart theorem is itself an RCD consequence in the manuscript's dimension range.
theorem NoncollapsedRCD.properSpace {K : ℝ} {n : ℕ} (hX : NoncollapsedRCD K n X) (hn : 2 ≤ n) : ProperSpace X := by …