English
Same as above in a version stated for Subalgebra.topologicalClosure_comap_homeomorph.
Русский
То же самое в версии для Subalgebra.topologicalClosure_comap_homeomorph.
LaTeX
$$$ s.topologicalClosure.comap f = (s.comap f).topologicalClosure $$$
Lean4
/-- If a subalgebra of a topological algebra is commutative, then so is its topological closure.
See note [reducible non-instances]. -/
abbrev commSemiringTopologicalClosure [T2Space A] (s : Subalgebra R A) (hs : ∀ x y : s, x * y = y * x) :
CommSemiring s.topologicalClosure :=
{ s.topologicalClosure.toSemiring, s.toSubmonoid.commMonoidTopologicalClosure hs with }