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Source labels openChecked July 26, 2026

Written on the Wall IICombinatorics

Written on the Wall II - Conjecture 133

Mathematical statement

WOWII Conjecture 133:

For a simple connected graph GG, path(G)rad(G)+avgvl(v)cC4(G)\operatorname{path}(G) \ge \operatorname{rad}(G) + \lfloor \mathrm{avg}_v\, l(v) \rfloor^{cC_4(G)}, where path(G)\operatorname{path}(G) is the path number of the graph (number of vertices of a largest induced path), rad(G)\operatorname{rad}(G) is the radius (minimum eccentricity, as a natural number), avgvl(v)=l(G)\mathrm{avg}_v\, l(v) = l(G) is the average independence number of vertex neighbourhoods, and cC4(G)cC_4(G) is the C4C_4-free characteristic function (1 if GG is C4C_4-free, not necessarily induced, and 0 otherwise).

We read DeLaVina's bracket notation [average of λ(v)] in the source as the floor (a standard Graffiti.pc convention), hence ⌊l G⌋ in Lean.

Statement source: Written on the Wall II statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

conjecture133

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem conjecture133 (G : SimpleGraph α) [DecidableRel G.Adj] (h : G.Connected) :    let rad := G.radius.toNat    let hasC4 :=  a b c d : α, a  b  a  c  a  d  b  c  b  d  c  d       G.Adj a b  G.Adj b c  G.Adj c d  G.Adj d a    let cC4 :  := if hasC4 then 0 else 1    (rad : ) + (⌊l G⌋ : ) ^ cC4  (path G : ) := by  sorry
Statement source
Formal Conjectures
Lean version
v4.27.0
Placeholder
Present; no proof artifact
Source evidence
Pinned source index
Fidelity review
Community formulation

References