K-local-ringed spaces #
Hironaka's analytic K-spaces, K = ℝ or ℂ, are K-local-ringed spaces: local-ringed spaces
with a structural morphism to Spec K, forming the category ℜ/K of which the analytic
K-spaces are the full subcategory An/K [Hir64, Ch. 0, §1, pp. 119–121]. This file defines
them and the constructions the rest of the theory rests on: the open subspace X | U, and the
K-local-ringed space (M, 𝒪_M) of an analytic manifold together with the K-morphism of an
analytic map.
The K-structure #
The K-structure is data: a ring homomorphism K →+* Γ(X, 𝒪_X). By the adjunction between
global sections and Spec on locally ringed spaces this is the same as a morphism X → Spec K,
and it keeps K : Type while the carrier lives in an arbitrary universe. Morphisms of locally
ringed spaces need not respect it: over ℂ the map f(z) ↦ conj (f (conj z)) is a ring
automorphism of the convergent power series ring ℂ{z} that is not ℂ-linear, and over ℝ a
nonzero ℚ-derivation d of ℝ gives the ring homomorphism r ↦ r + d(r) ε into ℝ[ε]/(ε²),
different from the canonical one. The morphisms of K-local-ringed spaces are therefore the
K-morphisms: morphisms of locally ringed spaces that commute with the structural homomorphisms
on global sections. Every restriction map and every stalk map of a K-morphism is then
K-linear (Hom.algebraMap_res, Hom.algebraMap_stalk).
Main definitions #
KLocallyRingedSpace K: aLocallyRingedSpacewithalgebraMap : K →+* Γ(X, 𝒪_X), with its category (theK-morphisms),KIso(theK-isomorphisms) andHom.toFun(the underlying continuous map);Hom.ofFac: a factorization of aK-morphism through aK-morphism is aK-morphism.KLocallyRingedSpace.restrictOpen X U: the open subspaceX | U, the restriction of the locally ringed space along the open embedding ofUwith the restrictedK-structure, and the open immersionofRestrict : X | U ⟶ Xas aK-morphism.KLocallyRingedSpace.ofManifold K E M: the locally ringed space(M, 𝒪_M)of an analytic manifoldMmodelled onE,𝒪_Mthe sheaf of analytic functions, with the constants asK-structure. ForM = Kⁿthis is Hironaka's(Kⁿ, 𝒜_{Kⁿ})(AnalyticSpace.affine), and𝒜_Gfor an openG ⊆ Kⁿis its restrictionrestrictOpen, as Hironaka defines it.ofManifoldHom f hf : ofManifold K E M ⟶ ofManifold K E' N, theK-morphism induced by an analytic mapf : M → N, the analytic analogue of Mathlib'sChartedSpace.locallyRingedSpaceMapfor smooth manifolds: the base map isf; the sheaf map𝒪_N ⟶ f_* 𝒪_Mis precomposition withf, an analytic functiongonU ⊆ Ngoing tog ∘ fonf⁻¹(U)(ofManifoldSheafHom); the stalk maps𝒪_{N, f x} → 𝒪_{M, x}are local, because the value atxofg ∘ fis the value atf xofg(stalkMap_ofManifoldHomAux_evalHom) and a germ is a unit exactly when its value is nonzero; theK-structure is respected, a constant pulling back to the same constant. The model spacesE,E'of source and target may differ: a chartφ : U → Eis an analytic map into the manifoldE, and an open subset ofKⁿis a manifold modelled onKⁿ. This is the morphism part of the functorSpfrom analytic manifolds to the analyticK-spaces of [Hir64, Ch. 0, §1, pp. 119–120] (AnalyticSpace.toSpaceHom).
A K-local-ringed space [Hir64, Ch. 0, §1, p. 119]: a locally ringed space X together with
its structural homomorphism algebraMap : K →+* Γ(X, 𝒪_X), the ring-homomorphism form of a
morphism X → Spec K.
- algebraMap : K →+* ↑(AlgebraicGeometry.LocallyRingedSpace.Γ.obj (Opposite.op self.toLocallyRingedSpace))
The
K-structure: the constantsK → Γ(X, 𝒪_X).
Instances For
Equations
- AnalyticSpace.KLocallyRingedSpace.instCoeSortType = { coe := fun (X : AnalyticSpace.KLocallyRingedSpace K) => ↑↑X.toPresheafedSpace }
The K-morphisms [Hir64, Ch. 0, §1, p. 121]: the morphisms of locally ringed spaces that
commute with the structural homomorphisms on global sections.
Equations
- X.Hom Y = { f : X.toLocallyRingedSpace ⟶ Y.toLocallyRingedSpace // (CommRingCat.Hom.hom (AlgebraicGeometry.LocallyRingedSpace.Γ.map f.op)).comp Y.algebraMap = X.algebraMap }
Instances For
The category ℜ/K of K-local-ringed spaces [Hir64, Ch. 0, §1, p. 121].
Equations
- One or more equations did not get rendered due to their size.
A K-morphism is determined by its underlying morphism of locally ringed spaces; the
K-condition is a proposition.
The underlying continuous map of a K-morphism.
Equations
Instances For
K-isomorphisms: the isomorphisms of the category ℜ/K (Hironaka's "K-isomorphic").
Instances For
A factorization l of the K-morphism a through the K-morphism b is a K-morphism.
Equations
- AnalyticSpace.KLocallyRingedSpace.Hom.ofFac a b l hl = ⟨l, ⋯⟩
Instances For
The open subspace X | U [Hir64, Ch. 0, §1, p. 120]: the restriction of the locally ringed
space along the open embedding of U, with the K-structure obtained by restricting the
constants.
Equations
- X.restrictOpen U = { toLocallyRingedSpace := X.restrict ⋯, algebraMap := (CommRingCat.Hom.hom (AlgebraicGeometry.LocallyRingedSpace.Γ.map (X.ofRestrict ⋯).op)).comp X.algebraMap }
Instances For
The open immersion X | U ⟶ X as a K-morphism.
Equations
- X.ofRestrict U = ⟨X.ofRestrict ⋯, ⋯⟩
Instances For
The locally ringed space (M, 𝒪_M) of an analytic manifold M modelled on E: 𝒪_M is the
sheaf of analytic functions on M, whose stalks are local rings, and the constants give the
K-structure. For M = Kⁿ this is Hironaka's (Kⁿ, 𝒜_{Kⁿ}), 𝒜_{Kⁿ} the sheaf of germs of
analytic K-functions on Kⁿ, with the convergent power series rings K{z₁ - x₁, …, zₙ - xₙ}
as stalks [Hir64, Ch. 0, §1].
Equations
- One or more equations did not get rendered due to their size.
Instances For
The K-morphism of an analytic map #
A map into an open subset U of a manifold is C^n iff it is C^n as a map into the manifold
(Mathlib's ChartedSpace.liftPropWithinAt_subtypeVal_comp_iff, for every n).
The continuous map underlying an analytic map, as a morphism of TopCat.
Equations
- AnalyticSpace.KLocallyRingedSpace.ofManifoldBase f hf = TopCat.ofHom { toFun := f, continuous_toFun := ⋯ }
Instances For
The sheaf map of an analytic map, 𝒪_N ⟶ f_* 𝒪_M: precomposition with f, an analytic
function g on U ⊆ N going to g ∘ f on f⁻¹(U).
Equations
- One or more equations did not get rendered due to their size.
Instances For
(Implementation.) The morphism of presheafed spaces underlying ofManifoldHom.
Equations
Instances For
The stalk map of an analytic map followed by evaluation at x is evaluation at f x.
The evaluation at x of the stalk map applied to a germ at f x is the evaluation of the
germ at f x.
The K-morphism induced by an analytic map f : M → N: base map f, sheaf map
precomposition with f; the stalk maps are local since evaluation is preserved and a germ is a unit
exactly when its value is nonzero; constants go to constants.
Equations
- AnalyticSpace.KLocallyRingedSpace.ofManifoldHom f hf = ⟨let __spread.0 := AnalyticSpace.KLocallyRingedSpace.ofManifoldHomAux f hf; { toHom := __spread.0, prop := ⋯ }, ⋯⟩