English
Eq of submodule_of for a span and a submodule: the span of x inside N equals span{⟨x, hx⟩}.
Русский
Эквивалентность подпространств: спан x внутри N равен спану ⟨x, hx⟩.
LaTeX
$$$((\operatorname{span} R\{x\}).submoduleOf N) = (\operatorname{span} R\{\langle x, hx\rangle\})$$$
Lean4
/-- Two linear maps are equal on `Submodule.span s` iff they are equal on `s`. -/
theorem eqOn_span_iff {s : Set M} {f g : F} : Set.EqOn f g (span R s) ↔ Set.EqOn f g s := by rw [← le_eqLocus, span_le];
rfl