Mathesis

Dirac's lemma, strong form: in a chordless-cycle-free adjacency structure, every vertex set is a clique or contains two nonadjacent simplicial vertices.

DeclHiddenChannelCapacity.dirac_strong
∀ {ι : Type u_1} [inst : DecidableEq ι] (𝒞 : Finset (Finset ι)),
  (¬∃ l, HiddenChannelCapacity.IsChordlessCycle 𝒞 l) →
    ∀ (S : Finset ι),
      (∀ x ∈ S, ∀ y ∈ S, x ≠ y → HiddenChannelCapacity.Adj 𝒞 x y) ∨
        ∃ u w,
          HiddenChannelCapacity.SimpIn 𝒞 S u ∧
            HiddenChannelCapacity.SimpIn 𝒞 S w ∧ u ≠ w ∧ ¬HiddenChannelCapacity.Adj 𝒞 u w

Arguments

DOIAuthorDate
MTH.R-2026-6020Dhruv GuptaDhruv Gupta2026-09-24T00:00:00Z
DOIMTH.C-2026-6020
Cite

Verification

Library
ZPM.Measurements.HC.Dirac
Statement digest
e606da67595a
First verified
2026-09-24T00:00:00Z