Minimum Edge-Outerplanar Embeddings are Polynomial-Time Computable

Hantao Yu

A polynomial-time algorithm finds a planar embedding of minimum edge-outerplanarity for every finite loopless planar graph, including graphs with parallel edges. It reduces edge-peeling depth to minimum face-depth of an auxiliary planar graph.

Sources for this record

What was already known

Bentz posed the optimization question in 2009. Polynomial-time algorithms were known for ordinary vertex outerplanarity and minimum face-depth.

AI involvement AI-led

GPT 5.5 Pro produced the initial proof, Claude Opus 4.8 reviewed it, and Hantao Yu manually verified and polished the argument.

The source directly credits GPT 5.5 Pro as solver of the initial complete proof, followed by model and author verification.

Importance Notable

The reduction answers Bentz’s algorithmic question for loopless planar graphs.

Limitations

The paper gives a polynomial-time guarantee but does not state a tighter runtime for the final reduction or detail every model-to-human proof edit.

Technical verification Formal (human)

The author expressly says he verified the generated proof before publication. This is a source-reported completed human check of Theorem 1.1; the Claude verifier is not counted as a machine proof check.

Formal checking

Manual verification and polishing of the GPT-generated proof

Checker
Hantao Yu, author
Scope
Theorem 1.1 polynomial-time minimum edge-outerplanar embedding for finite loopless planar graphs
Basis
Reported by the linked checker
Evidence source

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

Human understanding Full

Yu explains why edge-peeling layers equal face-adjacency depth and why the auxiliary graph preserves the optimum, including disconnected components.

Correction and publication history