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Towards schemes of finite presentation without size issues #1080

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@mzeuner mzeuner commented Nov 17, 2023

Redoing the relevant parts of #1068 for finitely presented algebras and this time without raising universe levels.

@mzeuner mzeuner marked this pull request as draft November 30, 2023 13:04
-- the Zariski lattice (classifying compact open subobjects)
private forget = ForgetfulCommAlgebra→CommRing R

𝓛 : fpAlgFunctor
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This should probably be defined by just composing the functor forget with the Z-functor version of 𝓛.

isAffine X = ∃[ A ∈ SmallFPAlgebra ] (Sp .F-ob A) ≅ᶜ X

-- the induced subfunctor
⟦_⟧ᶜᵒ : {X : fpAlgFunctor} (U : CompactOpen X) → fpAlgFunctor
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Maybe this should be defined by just taking the pullback of U and the "top element inclusion" of the lattice?

isAffineCompactOpen U = isAffine ⟦ U ⟧ᶜᵒ

-- the dist. lattice of compact opens
CompOpenDistLattice : Functor fpAlgFUNCTOR (DistLatticesCategory {ℓ} ^op)
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"Homework" question for us: Can this be unified with the very similar construction of the "global sections functor" that maps X to X ⇒ 𝔸¹?

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