erdős #1077
We call a graph -balanced (or -almost-regular) if the maximum degree is at most times the minimum degree.Let and and be sufficiently large. If is a graph on vertices with at least edges, then must contain a -balanced subgraph on vertices with at least edges?
Worked, still open.
graph theory · solved · formalized (Lean) · 0 attempts
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vela registry pull vfr_37aec80d874a0239vela reproduce examples/erdos-problemsformal
AMS 5 · solved (literature)
theorem erdos_1077 :
answer(False) ↔ ∀ ε > (0 : ℝ), ε < 1 → ∀ α > (0 : ℝ), α < 1 → ∀ᶠ D in atTop, ∀ᶠ n in atTop,
∀ G : SimpleGraph (Fin n), G.edgeSet.ncard > (n : ℝ) ^ (1 + α) →
∃ (H : Subgraph G),
letI m := H.verts.ncard
IsBalanced H.coe D ∧
m > (n : ℝ) ^ (1 - α) ∧
H.edgeSet.ncard > ε * m ^ (1 + α)formal-conjectures/1077.lean ↗status
solved