fintype instances for sigma types #
@[instance_reducible]
instance Sigma.instFintype {ι : Type u_1} {κ : ι → Type u_3} [(i : ι) → Fintype (κ i)] [Fintype ι] :
Fintype ((i : ι) × κ i)
Equations
- Sigma.instFintype = { elems := Finset.univ.sigma fun (x : ι) => Finset.univ, complete := ⋯ }
@[instance_reducible]
instance PSigma.instFintype {ι : Type u_1} {κ : ι → Type u_3} [(i : ι) → Fintype (κ i)] [Fintype ι] :
Fintype ((i : ι) ×' κ i)
Equations
- PSigma.instFintype = Fintype.ofEquiv ((i : ι) × κ i) (Equiv.psigmaEquivSigma κ).symm