Documentation

Mathlib.Data.Finsupp.Pointwise

The pointwise product on Finsupp. #

For the convolution product on Finsupp when the domain has a binary operation, see the type synonyms AddMonoidAlgebra (which is in turn used to define Polynomial and MvPolynomial) and MonoidAlgebra.

Declarations about the pointwise product on Finsupps #

instance Finsupp.instMul {α : Type u₁} {β : Type u₂} [MulZeroClass β] :
Mul (α →₀ β)

The product of f g : α →₀ β is the finitely supported function whose value at a is f a * g a.

Equations
    theorem Finsupp.coe_mul {α : Type u₁} {β : Type u₂} [MulZeroClass β] (g₁ g₂ : α →₀ β) :
    ⇑(g₁ * g₂) = g₁ * g₂
    @[simp]
    theorem Finsupp.mul_apply {α : Type u₁} {β : Type u₂} [MulZeroClass β] {g₁ g₂ : α →₀ β} {a : α} :
    (g₁ * g₂) a = g₁ a * g₂ a
    @[simp]
    theorem Finsupp.single_mul {α : Type u₁} {β : Type u₂} [MulZeroClass β] (a : α) (b₁ b₂ : β) :
    (fun₀ | a => b₁ * b₂) = (fun₀ | a => b₁) * fun₀ | a => b₂
    theorem Finsupp.support_mul_subset_left {α : Type u₁} {β : Type u₂} [MulZeroClass β] {g₁ g₂ : α →₀ β} :
    (g₁ * g₂).support g₁.support
    theorem Finsupp.support_mul_subset_right {α : Type u₁} {β : Type u₂} [MulZeroClass β] {g₁ g₂ : α →₀ β} :
    (g₁ * g₂).support g₂.support
    theorem Finsupp.support_mul {α : Type u₁} {β : Type u₂} [MulZeroClass β] [DecidableEq α] {g₁ g₂ : α →₀ β} :
    (g₁ * g₂).support g₁.support g₂.support
    instance Finsupp.instMulZeroClass {α : Type u₁} {β : Type u₂} [MulZeroClass β] :
    Equations
      instance Finsupp.instNonUnitalRing {α : Type u₁} {β : Type u₂} [NonUnitalRing β] :
      Equations
        @[reducible, inline]
        abbrev Finsupp.pointwiseScalar {α : Type u₁} {β : Type u₂} {M : Type u_1} [Zero M] [SMulZeroClass β M] :
        SMul (αβ) (α →₀ M)

        Pointwise scalar multiplication given by (f • g) x = f x • g x.

        Equations
          Instances For
            instance Finsupp.pointwiseScalarSemiring {α : Type u₁} {β : Type u₂} [Semiring β] :
            SMul (αβ) (α →₀ β)
            Equations
              @[simp]
              theorem Finsupp.coe_pointwise_smul {α : Type u₁} {β : Type u₂} [Semiring β] (f : αβ) (g : α →₀ β) :
              ⇑(f g) = f g
              instance Finsupp.pointwiseModule {α : Type u₁} {β : Type u₂} [Semiring β] :
              Module (αβ) (α →₀ β)

              The pointwise multiplicative action of functions on finitely supported functions

              Equations