Polynomial neighborhood complexity from bounded VC-dimension
Lax185574.NeighborhoodComplexityBound · concepts/Lax185574/NeighborhoodComplexityBound.lean · lax-185574
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Lemma
If G has VC-dimension d then
π_G(k) ≤ (k + 1)^d for all k ∈ ℕ.
This follows from the Sauer–Shelah lemma.
Concept map
Evidence
Each proof establishes this claim relative to its assumptions.
In the paper
- page 13 of this submission's paper
Lean source view on GitHub
| 1 | import Lax185574.VCDimension |
| 2 | |
| 3 | /-! |
| 4 | --- |
| 5 | title: Polynomial neighborhood complexity from bounded VC-dimension |
| 6 | type: lemma |
| 7 | --- |
| 8 | If G has VC-dimension d then |
| 9 | |
| 10 | π_G(k) ≤ (k + 1)^d for all k ∈ ℕ. |
| 11 | |
| 12 | This follows from the Sauer–Shelah lemma. |
| 13 | |
| 14 | # Formalization notes |
| 15 | |
| 16 | The hypothesis is VC-dimension at most d, which is equivalent: a graph |
| 17 | of VC-dimension d' ≤ d satisfies the bound for d', hence for d. The |
| 18 | graph may be infinite. Its VC-dimension is then an extended natural |
| 19 | number, and the hypothesis excludes the value ⊤. |
| 20 | -/ |
| 21 | |
| 22 | namespace Lax185574.NeighborhoodComplexityBound |
| 23 | |
| 24 | open Lax185574.VCDimension |
| 25 | |
| 26 | universe u |
| 27 | |
| 28 | /-- **Neighborhood complexity bound.** A graph of VC-dimension at most `d` has |
| 29 | neighborhood complexity `π_G(k) ≤ (k + 1)^d`. -/ |
| 30 | axiom neighborhoodComplexity_le {V : Type u} (G : SimpleGraph V) (d : ℕ) |
| 31 | (hG : vcDim G ≤ d) (k : ℕ) : neighborhoodComplexity G k ≤ (k + 1) ^ d |
| 32 | |
| 33 | end Lax185574.NeighborhoodComplexityBound |
| 34 |
Formalization notes
The hypothesis is VC-dimension at most d, which is equivalent: a graph of VC-dimension d' ≤ d satisfies the bound for d', hence for d. The graph may be infinite. Its VC-dimension is then an extended natural number, and the hypothesis excludes the value ⊤.
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