OAI/Combinatorics/EditApproximation/Geometry/TreeAccounting.lean

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Finite comparison-tree accounting

A complete tree is indexed by its physical depth and child labels. Terminal comparison costs may be carried forward, with zero costs in the other child slots. The identities apply to that representation without any probability or sampling hypothesis.

  1. theorem OAI.EditApproximation.tree_layer_sum line 25

    Source documentation

    Labeled nodes of a complete M-ary tree at one physical depth.

    theorem tree_layer_sum {M d : ℕ} (weight : TreeLayer M (d + 1) → ℝ) :
        (∑ node : TreeLayer M d, ∑ child : Fin M, weight (node, child)) =
          ∑ node : TreeLayer M (d + 1), weight node := by
    …

    Mentions: OAI.EditApproximation.TreeLayer

  2. theorem OAI.EditApproximation.tree_frontier_telescope line 31

    Source documentation

    Mass/energy differences cancel exactly between successive frontiers.

    theorem tree_frontier_telescope (M J : ℕ)
        (weight : (d : ℕ) → TreeLayer M d → ℝ) :
        (∑ d ∈ range J, ∑ node : TreeLayer M d,
          (weight d node - ∑ child : Fin M, weight (d + 1) (node, child))) =
            weight 0 PUnit.unit - ∑ node : TreeLayer M J, weight J node := by
    …

    Mentions: OAI.EditApproximation.TreeLayer

  3. theorem OAI.EditApproximation.small_growth_pow line 52

    Source documentation

    The explicit small-growth bound used for the comparison frontiers.

    theorem small_growth_pow {x : ℝ} (n : ℕ) (hx : 0 ≤ x)
        (hsmall : (n : ℝ) * x ≤ 1 / 2) :
        (1 + x) ^ n ≤ 1 + 2 * n * x := by
    …
  4. theorem OAI.EditApproximation.curvature_total_from_telescope line 73

    Source documentation

    The final scalar summation of the local curvature/energy estimates. The conservation identities are supplied by tree_frontier_telescope for the comparison masses and energies.

    theorem curvature_total_from_telescope {ι : Type*} (nodes : Finset ι)
        (curvature discrepancy massDifference movement slack energyDifference : ι → ℝ)
        (D rootMass terminalMass : ℝ)
        (hroot : 0 ≤ rootMass) (hterminal : terminalMass ≤ 2 * D)
        (hconservation : (∑ v ∈ nodes, massDifference v) = rootMass - terminalMass)
        (henergy : (∑ v ∈ nodes, energyDifference v) ≤ 2 * D)
        (hdiscrepancy : ∀ v ∈ nodes, 0 ≤ discrepancy v)
        (hslackNonneg : ∀ v ∈ nodes, 0 ≤ slack v)
        (hslack : ∀ v ∈ nodes, massDifference v + discrepancy v ≤ slack v)
        (hcurvature : ∀ v ∈ nodes, curvature v ≤ energyDifference v + 3 * movement v +
          2 * max (-massDifference v) 0) :
        (∑ v ∈ nodes, (curvature v + discrepancy v)) ≤
    …
  5. theorem OAI.EditApproximation.curvature_total_parameter_bound line 125

    Source documentation

    Substituting the endpoint and warmup slack totals gives the manuscript's stated curvature constant. Here u=J/P and v=J/T.

    theorem curvature_total_parameter_bound {total movement slack D F u v : ℝ}
        (hD : 0 ≤ D) (hF : 1 ≤ F) (hu : 0 ≤ u) (hv : 0 ≤ v)
        (htotal : total ≤ 8 * D + 3 * movement + 4 * slack)
        (hmove : movement ≤ 4 * u * D)
        (hslack : slack ≤ 512 * F * u * D + 4 * F * v * D) :
        total ≤ 5000 * F * (1 + u + v) * D := by
    …
  6. theorem OAI.EditApproximation.bad_node_cost_from_curvature line 144

    Source documentation

    Exceptional-node cost uses the total curvature/discrepancy charge; no count of nodes or independence assumption is needed.

    theorem bad_node_cost_from_curvature {ι : Type*} (nodes : Finset ι)
        (cost scale curvature discrepancy : ι → ℝ) (ratio totalBound : ℝ)
        (hratio : 0 ≤ ratio)
        (hcost : ∀ i ∈ nodes, cost i ≤ 2 * scale i)
        (hcurvature : ∀ i ∈ nodes, 0 ≤ curvature i)
        (hdiscrepancy : ∀ i ∈ nodes, 0 ≤ discrepancy i)
        (htotal : (∑ i ∈ nodes, (curvature i + discrepancy i)) ≤ totalBound) :
        (∑ i ∈ nodes with scale i < ratio * curvature i ∨ scale i < ratio * discrepancy i,
          cost i) ≤ 2 * ratio * totalBound := by
    …