English
The operation filter p defines a linear map on the DFinsupp family.
Русский
Операция фильтрации по p определяет линейное отображение на семействе DFinsupp.
LaTeX
$$$$ \\mathrm{filterLinearMap}: (p) \\to_{\\\\ell} (DFinsupp \\; \\beta_i) $$$$
Lean4
/-- `DFinsupp.filter` as a `LinearMap`. -/
@[simps]
def filterLinearMap [Semiring γ] [∀ i, AddCommMonoid (β i)] [∀ i, Module γ (β i)] (p : ι → Prop) [DecidablePred p] :
(Π₀ i, β i) →ₗ[γ] Π₀ i, β i where
toFun := filter p
map_add' := filter_add p
map_smul' := filter_smul p