Covers of schemes over a base #
In this file we define the typeclass Cover.Over. For a cover 𝒰 of an S-scheme X,
the datum 𝒰.Over S contains S-scheme structures on the components of 𝒰 and asserts
that the component maps are morphisms of S-schemes.
We provide instances of 𝒰.Over S for standard constructions on covers.
Bundle an S-scheme with P into an object of P.Over ⊤ S.
Equations
- X.asOverProp S h = { toComma := X.asOver S, prop := h }
Instances For
Bundle an S-morphism of S-scheme with P into a morphism in P.Over ⊤ S.
Equations
Instances For
A P-cover of a scheme X over S is a cover, where the components are over S and the
component maps commute with the structure morphisms.
- isOver_map (j : 𝒰.J) : Hom.IsOver (𝒰.map j) S
Instances
Equations
- S.instOverCoverOfIsIsoOfIsOver f = { over := fun (x : (AlgebraicGeometry.Scheme.coverOfIsIso f).J) => inferInstanceAs (X.Over S), isOver_map := ⋯ }
The pullback of a cover of S-schemes along a morphism of S-schemes. This is not
definitionally equal to AlgebraicGeometry.Scheme.Cover.pullbackCover, as here we take
the pullback in Over S, whose underlying scheme is only isomorphic but not equal to the
pullback in Scheme.
Equations
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Instances For
Equations
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Equations
- S.instOverPullbackCoverOver 𝒰 f = { over := inferInstance, isOver_map := ⋯ }
A variant of AlgebraicGeometry.Scheme.Cover.pullbackCoverOver with the arguments in the
fiber products flipped.
Equations
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Instances For
Equations
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Equations
- S.instOverPullbackCoverOver' 𝒰 f = { over := inferInstance, isOver_map := ⋯ }
The pullback of a cover of S-schemes with Q along a morphism of S-schemes. This is not
definitionally equal to AlgebraicGeometry.Scheme.Cover.pullbackCover, as here we take
the pullback in Q.Over ⊤ S, whose underlying scheme is only isomorphic but not equal to the
pullback in Scheme.
Equations
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Instances For
Equations
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Equations
- S.instOverPullbackCoverOverProp 𝒰 f hX hW hQ = { over := inferInstance, isOver_map := ⋯ }
A variant of AlgebraicGeometry.Scheme.Cover.pullbackCoverOverProp with the arguments in the
fiber products flipped.
Equations
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Instances For
Equations
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Equations
- S.instOverPullbackCoverOverProp' 𝒰 f hX hW hQ = { over := inferInstance, isOver_map := ⋯ }
Equations
- S.instOverObjBind 𝒰 𝒱 j = inferInstanceAs (((𝒱 j.fst).obj j.snd).Over S)