English
In the namespace of sequential closed sets, seqClosure s equals s when s is sequentially closed.
Русский
В рамках понятия последовательной замкнутости, seqClosure s совпадает с s, когда s последовательнос замкнуто.
LaTeX
$$$ \mathrm{IsSeqClosed}(s) \Rightarrow \mathrm{seqClosure}(s) = s $$$
Lean4
/-- The sequential closure of a sequentially closed set is the set itself. -/
theorem seqClosure_eq {s : Set X} (hs : IsSeqClosed s) : seqClosure s = s :=
Subset.antisymm (fun _p ⟨_x, hx, hp⟩ => hs hx hp) subset_seqClosure