English
The topological closure of a subalgebra is a subalgebra whose carrier is the closure of the original carrier.
Русский
Топологическое замыкание подалгебры является подалгеброй, носителем которой является замыкание исходного носителя.
LaTeX
$$carrier( s.topologicalClosure ) = closure( carrier(s) )$$
Lean4
/-- The topological closure of a subalgebra -/
def _root_.Subalgebra.topologicalClosure (s : Subalgebra R A) : Subalgebra R A
where
toSubsemiring := s.toSubsemiring.topologicalClosure
algebraMap_mem'
r :=
by
simp only [Subsemiring.coe_carrier_toSubmonoid, Subsemiring.topologicalClosure_coe, Subalgebra.coe_toSubsemiring]
apply subset_closure
exact algebraMap_mem s r