English
For a set s ⊆ M and t ⊆ α, the smul-closure satisfies s • closure t ⊆ closure (s • t).
Русский
Для множества s ⊆ M и t ⊆ α выполняется s • closure t ⊆ closure (s • t).
LaTeX
$$$ s \\;\\mathrm{•} \\; \\overline{t} \\subseteq \\overline{ s \\;\\mathrm{•} \\; t } $$$
Lean4
@[to_additive]
theorem set_smul_closure_subset (s : Set M) (t : Set α) : s • closure t ⊆ closure (s • t) :=
by
simp only [← iUnion_smul_set]
exact
iUnion₂_subset fun c hc ↦ (smul_closure_subset c t).trans <| closure_mono <| subset_biUnion_of_mem (u := (· • t)) hc