Exact-Mean Decompositions for Cost-Preserving Single-Source Unsplittable Flows: Demand Scales and Local Interaction Structure

Sergey Nikolenko

Nikolenko gives a six-terminal planar instance requiring congestion factor at least 58676765987259/50000000000000, or 1.17353531974518, under cost nonincrease. He also identifies exact local envelopes E(2)=1, E(3)=9/8 and E(4)=(299−41√41)/32.

Sources for this record

What was already known

An earlier planar example gave 1.139747…; an unconditional planar ceiling of 2 was known. The E(3) and E(4) numbers were earlier lower-bound examples, not exact envelope theorems.

AI involvement AI-centered

Nikolenko directed and wrote the project and reports verifying this paper. He credits GPT-5.6 Sol, Claude Fable 5 and Claude Opus 5 with most key ideas, proofs and verification tools, without assigning individual steps.

The paper explicitly says models supplied most key ideas in the work, including proofs; the particular idea-by-idea attribution remains unresolved.

Importance Notable

The planar lower bound improves and the local envelope theorems sharpen the restricted theory.

Limitations

The envelope and decomposition bounds are class-specific; none is a universal upper bound. The public flow counterexample and assigned four-terminal planar value concern earlier, weaker witnesses.

Technical verification Formal (exact rational computation + human)

Nikolenko reports checking the entire paper. The finite planar witness and envelope certificate ledger were also checked with exact arithmetic and second implementations. These are source-reported checks; the full pipeline was not run here.

Independent checking

Personally verified and edited the complete manuscript

Checker
Sergey Nikolenko, author
Scope
Paper III’s planar lower bound and local-envelope theorems
Basis
Reported by the linked checker
Evidence source

Formal checking

Exact rational certificate checks, including raw-arc reconstruction and second implementations

Checker
Project’s separately written certificate implementations
Scope
Six-terminal planar witness and 2,015-cell E(4) closure ledger
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

Nikolenko explains the exact-mean principle, factorization, bad-state/cover duality and why the earlier lower-bound examples become local envelopes.

Correction and publication history

2026-10-18 · publication

The planar lower bound improves and the local envelope theorems sharpen the restricted theory.

Read this published revision