`BookProof.ChapterPinOmega.Omega_inv` : ∀ x ∈ Omega, ∃ y ∈ Omega, x * y = 1 ∧ y * x = 1

Initializing...

`BookProof.ChapterPinOmega.Omega_inv` : ∀ x ∈ Omega, ∃ y ∈ Omega, x * y = 1 ∧ y * x = 1 · Prove2Me