English
The canonical sumEmpty diffeomorphism corresponds to Equiv.sumEmpty on the underlying types.
Русский
Каноническое отображение sumEmpty совпадает с Equiv.sumEmpty.
LaTeX
$$$ sumEmpty I I (M \\oplus M') M n = Equiv.sumEmpty M M' $$$
Lean4
/-- The canonical diffeomorphism `M ⊕ ∅ → M` -/
def sumEmpty [IsEmpty M'] : Diffeomorph I I (M ⊕ M') M n
where
toEquiv := Equiv.sumEmpty M M'
contMDiff_toFun := contMDiff_id.sumElim fun x ↦ (IsEmpty.false x).elim
contMDiff_invFun := ContMDiff.inl