All open problems
Source labels openChecked July 26, 2026

Written on the Wall IICombinatorics

Written on the Wall II - Conjecture 200

Mathematical statement

WOWII Conjecture 200

For a simple connected graph G, if tree(G) = ⌈1 + l_avg(G)⌉, then G has a Hamiltonian path. Here tree(G) is the number of vertices of a largest induced tree subgraph, and l_avg(G) = averageIndepNeighbors G is the average over all vertices of the independence number of the neighbourhood. A Hamiltonian path is a walk visiting every vertex exactly once.

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

conjecture200

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem conjecture200 (G : SimpleGraph α) (h : G.Connected)    (htree : (largestInducedTreeSize G : ) =1 + averageIndepNeighbors G⌉) :     a b : α,  p : G.Walk a b, p.IsHamiltonian := 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