English
For rings R,S with an algebra structure, the map algebraMap R S is formally smooth if and only if S is formally smooth as an R-algebra.
Русский
Пусть есть алгебраическая структура R→S; тогда algebraMap R S формально гладок тогда и только тогда, когда S формально гладко над R.
LaTeX
$$$\big( \text{algebraMap } R S \big).\mathrm{FormallySmooth} \iff \mathrm{Algebra.FormallySmooth}(R,S)$$$
Lean4
theorem formallySmooth_algebraMap [Algebra R S] : (algebraMap R S).FormallySmooth ↔ Algebra.FormallySmooth R S := by
rw [FormallySmooth, toAlgebra_algebraMap]