OAI/Topology/CoarseAssembly/SeparatedGeometry.lean

GitHub source file

5 declarations, 0 contain sorry, 0 declared as axioms

Bounded geometry of the separated union

Uniform component ball bounds pass to the union. All cross-component pairs in a fixed distance range lie in a finite prefix, which also supplies the finite exceptional set in the transfer argument.

  1. def OAI.CoarseAssembly.componentPrefix line 20
  2. theorem OAI.CoarseAssembly.mem_componentPrefix line 24
  3. theorem OAI.CoarseAssembly.finite_cross_pairs line 30
  4. theorem OAI.CoarseAssembly.separated_uniform_finite_balls line 42

    Source documentation

    The bounded-geometry hypothesis needed by the Roe transfer is preserved by this separated union.

    theorem separated_uniform_finite_balls (o : ∀ i, V i)
        (hcomp : ∀ R : ℝ, 0 ≤ R → ∃ N : ℕ, ∀ i (x : V i), ∃ b : Finset (V i),
          (∀ y, y ∈ b ↔ dist x y ≤ R) ∧ b.card ≤ N) :
        @UniformFiniteBalls (Sigma V) (separatedMetric o).toPseudoMetricSpace := by
    …

    Mentions: OAI.CoarseAssembly.UniformFiniteBalls, OAI.CoarseAssembly.separatedMetric

  5. theorem OAI.CoarseAssembly.separated_uniform_discrete line 80

    Source documentation

    Unit separation in each component gives unit separation in the union.

    theorem separated_uniform_discrete (o : ∀ i, V i)
        (hcomp : ∀ i (x y : V i), x ≠ y → 1 ≤ dist x y)
        (x y : Sigma V) (hxy : x ≠ y) : 1 ≤ separatedDist o x y := by
    …

    Mentions: OAI.CoarseAssembly.separatedDist