∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {F : Type u_8} [inst_1 : NormedAddCommGroup F]
  [inst_2 : NormedSpace 𝕜 F] (b b' x : F),
  (tangentBundleCore (modelWithCornersSelf 𝕜 F) F).coordChange (achart F b) (achart F b') x = 1