`BookProof.ChapterA3o.sum_signed_permMat_sq` {N : ℕ} : (∑ σ : Equiv.Perm (Fin N), signC σ • permMat σ) * (∑ σ : Equiv.Perm (Fin N), signC σ • permMat σ) = (Nat.factorial N :...

Initializing...

`BookProof.ChapterA3o.sum_signed_permMat_sq` {N : ℕ} : (∑ σ : Equiv.Perm (Fin N), signC σ • permMat σ) * (∑ σ : Equiv.Perm (Fin N), signC σ • permMat σ) = (Nat.factorial N :... · Prove2Me