Proof of `Twin-width is bounded by a function of mixed minor number`

groundedproofs/Lax49Proofs/TwinWidthFromMixedMinorNumber.lean · lax-49

What this proof establishes

no assumptions

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

Description

Twin-width (the parameter of submission Lax48) is bounded by a numerical function of the submitted mixed minor number.

Proof strategy

The source direction twinWidthBoundedByMixedMinorNumbertwinWidthBoundedByMixedMinorNumber is the mirrored Boolean Theorem 14 construction: an ordered adjacency matrix of mixed number kk is (k+1)(k+1)-mixed-free, and the Marcus–Tardos-based Theorem 10 machinery turns a mixed-free matrix into a contraction sequence of bounded red degree. Rewriting with the two parameter equalities of Lax49Proofs.BridgeLax49Proofs.Bridge moves the bound onto the submitted parameters, with the same witness function.

Attribution

Bonnet, Kim, Thomassé and Watrigant, Twin-width I: Tractable FO Model Checking (J. ACM 2022).