English
For a linearly independent set indexed by v with a subset s, the toENat of the rank of span of v''s image equals the encard of s.
Русский
Для линейно независимого множества, индексированного v, и подмножества s, toENat ранга порождаемого span(v''s) равен encard(s).
LaTeX
$$\n(\\operatorname{rank}_R(\\operatorname{span}_R( (v'' )s )).toENat = s.encard\n$$
Lean4
theorem rank_span_set {s : Set M} (hs : LinearIndepOn R id s) : Module.rank R ↑(span R s) = #s :=
by
rw [← @setOf_mem_eq _ s, ← Subtype.range_coe_subtype]
exact rank_span hs