sorry
V : Type u
R : Type v
inst✝² : Semiring R
inst✝¹ : Fintype V
G : SimpleGraph V
inst✝ : Nonempty V
h : ∀ ⦃v w : V⦄, v ≠ w → Fintype.card ↑(G.commonNeighbors v w) = 1
no_politician : ¬∃ v, ∀ (w : V), v ≠ w → G.Adj v w
lemma₁ : ∃ k, G.IsRegularOfDegree k
k : ℕ
hregular : G.IsRegularOfDegree k
n : ℕ := Fintype.card V
⊢ k + (n - 1) = k * k
no goals