English
If lsum restricted to each component is injective, then the family is iSupIndep.
Русский
Если отображение lsum по каждой компоненте инъективно, тогда семейство независимо по iSupIndep.
LaTeX
$$$iSupIndep p$ при условии инъективности $lsum \\dots$$$
Lean4
theorem iSupIndep_of_dfinsupp_lsum_injective (p : ι → Submodule R N)
(h : Function.Injective (lsum ℕ fun i => (p i).subtype)) : iSupIndep p :=
by
rw [iSupIndep_iff_forall_dfinsupp]
intro i x v hv
replace hv : lsum ℕ (fun i => (p i).subtype) (erase i v) = lsum ℕ (fun i => (p i).subtype) (single i x) := by
simpa only [lsum_single] using hv
have := DFunLike.ext_iff.mp (h hv) i
simpa [eq_comm] using this