Proof of `Polynomial bound on the number of types over a parameter set`

groundedproofs/Lax185574Proofs/TypeBound.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 29 of this submission's paper

Description

The proof in the paper, with the padding step replaced by a split of each tuple into its entries outside UU and its entries inside UU. Let r=r(q)r = r(q) be the separation radius. For each k′≤kk' ≤ k, the closure theorem for tuples gives polynomially many ss-flips HH of GG such that every k′k'-tuple outside UU is at distance more than rr from UU in one of them. A flip HH is undone by a toggle on at most ss parts, so the edges of GG are quantifier-free definable in HH expanded by the colors and by predicates for the parts, and the type of a tuple in this expansion H+H⁺ determines its type in G+G⁺. A kk-tuple vˉv̄ is a rearrangement of ā ū with ā outside UU and ū inside UU, and its type is determined by the type of ā ū and the positions. For fixed positions, ū, and HH, the tuples ā far from UU in HH realize at most T(q,k′,c+s)T(q, k', c + s) types in H+H⁺. Summing over at most 2k2^k position sets, (∣U∣+1)k(|U| + 1)^k tuples ū and the flips gives the bound, whose exponent does not depend on cc.

The argument is carried out for the graph classes of the archive and their monadic dependence, and transferred to the graph classes used here.