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Erdős problem 1036

Let GG be a graph on nn vertices which does not contain a trivial (empty or complete) graph on more than clognc\log n vertices. Must GG contain at least 2Ωc(n)2^{\Omega_c(n)} many induced subgraphs which are not pairwise isomorphic?

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FormalConjectures/ErdosProblems/

1036.lean

Retained formal statement1 of 3

Let GG be a graph on nn vertices which does not contain a trivial (empty or complete) graph on more than clognc\log n vertices. Must GG contain at least 2Ωc(n)2^{\Omega_c(n)} many induced subgraphs which are not pairwise isomorphic?

This is true, and was proved by Shelah [Sh98].

FormalConjectures/ErdosProblems/1036.leanErdos1036.erdos_10369 linesExact file
True  ∀ (c : ℝ),    0 < c      ∃ δ,        0 < δ ∧          ∀ᶠ (n : ℕ) in Filter.atTop,            ∀ (G : SimpleGraph (Fin n)),G.cliqueNumc * Real.lognG.indepNumc * Real.lognErdos1036.HasManyNonIsomorphicInducedSubgraphs G (2 ^ (δ * ↑n))
SolvedProof has a holelean4external proof

The proof uses `sorry`: part of the argument is written but not proved. Lean accepts the file; it does not accept the theorem.

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