Proof of `Computing locally definable construction sequences`

groundedproofs/Lax185574Proofs/DefinableSequences.lean · lax-185574

What this proof establishes

Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.

Read the Lean proof on GitHub

In the paper

  • page 31 of this submission's paper

Description

The proof of the theorem on definable construction sequences. Compute a chain at radius 5r+15r + 1 and accuracy εε (the chain theorem), of length m≤O(r/ε)m ≤ O(r/ε), and turn it into a construction sequence (the lemma turning chains into construction sequences). With kr≤c(n+1)εk_r ≤ c (n+1)^ε the radius-(5r+1)(5r+1) width of the chain, dd a bound on the VC-dimension of the graphs of the class (the observation on bounded VC-dimension) and πG(k)≤(k+1)dπ_G(k) ≤ (k+1)^d (the Sauer–Shelah lemma), wr≤(kr+1)(d+1)w_r ≤ (k_r + 1)^(d+1), so a0=d+1a₀ = d + 1. The length is O(nw1)≤O(nwr)O(n w₁) ≤ O(n w_r), as the width of a chain grows with the radius. The number of predicates is 2m+1≤⌈Ar/ε⌉+A2m + 1 ≤ ⌈A r/ε⌉ + A. On the word RAM, a first phase converts the compressed sparse row form of the graph into the word of the graph that the two cited programs read.

The proof is carried out for the input format with the graph in compressed sparse row form and the notion Lax185574.Computing.ComputesLax185574.Computing.Computes. The algorithm converts the word of the graph into compressed sparse rows (Interface.nbrbridgeInterface.nbr_bridge) and runs that program. The script of a graph is the one whose encoding the program outputs on the converted input.