Formal evidence
An independent reviewer must inspect the recorded build, declarations, unfinished-proof-step check, and disclosed foundations.
ProofAtlas research case study
Graph drawing · geometric routing · formal theorem
A paper and pinned Lean package give a proof candidate that every finite simple 3-connected plane graph has a convex greedy straight-line drawing preserving its prescribed embedding and outer face.
Scope: Every finite simple 3-connected plane graph, presented by an original continuous plane drawing, has a straight-line drawing that preserves its embedding and outer face, has strictly convex facial polygons, and admits a strictly closer adjacent step toward every distinct destination; the construction records a Euclidean decrease of at least 3/4 in its normalization.
Exact formal proposition
theorem strong_pr_conjecture
(hd : IsOriginalDrawing G Finset.univ p arc)
(hcard : 4 ≤ (Finset.univ : Finset V).card)
(hcuts : ∀ X : Finset V, X.card ≤ 2 → ConnectedOn G (Finset.univ \ X)) :
∃ (q : V → Plane)
(F : List (NativeFaceBoundary G))
(_ : IsNativeFaceFamily Finset.univ arc (mappedOriginalGraph G Finset.univ p) F)
(o : {f : NativeFaceBoundary G // f ∈ F})
(bodies : {f : NativeFaceBoundary G // f ∈ F} → Set Plane)
(H : Plane ≃ₜ Plane),
Function.Injective q
∧ IsOriginalDrawing G Finset.univ q (originalStraightArc q)
∧ (∀ s t : V, s ≠ t → ∃ a, G.Adj s a ∧ dist (q t) (q a) + 3 / 4 ≤ dist (q t) (q s))
∧ (∀ s t : V, s ≠ t → ∃ a, G.Adj s a ∧ 1 ≤ dist (q t) (q s)^2 - dist (q t) (q a)^2)
∧ (∀ (d : G.Dart) (v : V), q v ∈ segment ℝ (q d.fst) (q d.snd) ↔ v = d.fst ∨ v = d.snd)
∧ (∀ d e : G.Dart, d.edge ≠ e.edge → segment ℝ (q d.fst) (q d.snd) ∩ segment ℝ (q e.fst) (q
e.snd) = q '' (({d.fst, d.snd} : Set V) ∩ {e.fst, e.snd}))
∧ ¬Bornology.IsBounded o.val.region
∧ (∀ f : {f : NativeFaceBoundary G // f ∈ F}, IsStrictConvexCycle q (if f = o then
f.val.walk.reverse else f.val.walk) (bodies f))
∧ (∀ f : {f : NativeFaceBoundary G // f ∈ F}, H '' f.val.region = if f = o then (bodies f)ᶜ
else interior (bodies f))
∧ (∀ (f : {f : NativeFaceBoundary G // f ∈ F}) z, z ∈ (if f = o then (bodies f)ᶜ else
interior (bodies f)) → originalFace G Finset.univ q (originalStraightArc q) z = if f = o
then (bodies f)ᶜ else interior (bodies f))
∧ (∀ v : V, H (p v) = q v)
∧ (∀ (d : G.Dart) (t : unitInterval), H (hd.dartPath d (Finset.mem_univ _) (Finset.mem_univ
_) t) = Path.segment (q d.fst) (q d.snd) t)
∧ (∀ (η : C(unitInterval, Plane)) (hη : η 1 = η 0) (x : Plane) (hx : ∀ t, η t ≠ x),
planeLoopWinding ((H : C(Plane, Plane)).comp η) (congrArg H hη) (H x) (fun t he => hx t
(H.injective he)) = planeLoopWinding η hη x hx)
∧ ∀ d : G.Dart, IsStraightClockwiseSuccessor Finset.univ q d (nativeVertexPermutation F d)Result boundary
Every finite simple 3-connected plane graph, presented by an original continuous plane drawing, has a straight-line drawing that preserves its embedding and outer face, has strictly convex facial polygons, and admits a strictly closer adjacent step toward every distinct destination; the construction records a Euclidean decrease of at least 3/4 in its normalization.
Companion research paper
The September 9 paper proves that every finite simple 3-connected plane graph admits a convex greedy straight-line drawing preserving its prescribed embedding and outer face. An accompanying Lean 4 development checks the existence theorem from the original continuous plane drawing and three-connectivity assumptions.
Author-authorized early release. This fixed paper package first appeared while independent presentation review was pending; hosting it does not mark the Lean result accepted.
Hosting authorized by the rightsholder. ProofAtlas metadata cover; not a reproduction of a paper page or part of the proof.
Lech Mazur, “A Proof of the Strong Papadimitriou–Ratajczak Conjecture,” September 9, 2026.
Paper overview
Author-supplied explanation of the theorem, a representative dodecahedral drawing, the greedy routing rule, and the proof ingredients. It is explanatory, not proof or formal-verification evidence.

Line counts exclude blank lines; comments and documentation count. The total is the commit-pinned first-party Lean import closure; Mathlib and other third-party dependencies are excluded.
Continue the mathematics
The pinned theorem and its complete local import closure let people and AI agents inspect the proof, compare another route, isolate reusable lemmas, or formulate a stronger exact statement. Lean checks each proposed extension against its own exact statement.
The ZIP contains the checked first-party Lean import closure, exact statements and boundaries, license, notice, evidence, source-footprint manifest, and continuation data. Mathlib and other third-party dependencies are not bundled.
Publication review
Lean has checked the exact source; this public release is not presented as a ProofAtlas accepted result. The linked evidence page shows individual review decisions where they are publicly available. The requirements below describe publication coverage, not a count of unfinished reviews. Independent AI, human, or mixed reviewers may examine the build evidence, statement alignment, result boundary, and public wording. Review does not replace Lean's check or broaden the theorem.
An independent reviewer must inspect the recorded build, declarations, unfinished-proof-step check, and disclosed foundations.
The formal declaration must be reviewed against the theorem wording and its exact variant.
The limits must be checked so the page cannot imply a broader theorem.
The explanation, infographic labels, and source presentation need independent review.
The permanent source link and downloadable files must be approved for public citation.
After the four reviews and source route are ready, an accepted-result record must bind them to this exact formalization.
Credit for this release
Authorship and other contributions are recorded separately for this version.
OpenAI GPT-6 Pro and OpenAI Codex have source-reported roles in mathematical exploration, proof development, computational testing, Lean formalization, and exposition.
Lech Mazur is the paper author, accountable editor, and research director for the Strong Papadimitriou–Ratajczak result.
Citation
Use the version-specific citation so the authorship, scope, and public record remain attached.
Release history
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