Erdős problem 762
The cochromatic number of , denoted by , is the minimum number of colours needed to colour the vertices of such that each colour class induces either a complete graph or empty graph.
Sources
FormalConjectures/ErdosProblems/
762.lean
Retained formal statement
A conjecture of Erdős, Gimbel, and Straight [EGS90], who proved that for every there exists some such that if contains no clique on vertices then .
∀ (n : ℕ), 2 < n → ∃ f, ∀ (V : Type u_1) [Fintype V] (G : SimpleGraph V), G.CliqueFree n → G.chromaticNumber ≤ G.cochromaticNumber + ↑fSolvedStatement only, no proof