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Hironaka.AnalyticSpace.Manifold.Defs

The analytic space of an analytic manifold #

An analytic manifold M over K = ℝ or ℂ, modelled on a finite-dimensional normed space E with coordinates ψ : E ≃L[K] Kⁿ, is an analytic K-space in the sense of Hironaka Hir64, Ch. 0, §1, pp. 119–120: its structure sheaf is the sheaf of analytic functions, with the constants as K-structure, and (i) every point has a chart domain U on which Sp(M) | U is K-isomorphic to a local analytic K-space, namely the open G = ψ(φ.target) ⊆ Kⁿ with no equations (chartLocalModelIso); (ii) M is countable at infinity, being second countable and locally compact (the model space is finite-dimensional, hence proper, which is where the coordinates ψ enter); (iii) M is Hausdorff. This module defines

Sp is a functor from analytic manifolds to analytic K-spaces. It is fully faithful (toSpace_fullyFaithful); its behaviour on open submanifolds, closed submanifolds, disjoint unions and the dimension strata of a non-singular space is proved in the neighbouring modules. Through Sp the manifold-level results of the analytic strand (blow-ups of manifolds, ideal sheaves on manifolds, their strict transforms) are read as statements about analytic spaces; in particular the ambient blow-up factorization of the resolution theorem for analytic spaces (Hom.AmbientBlowUpFactorization) writes the closed subspaces of a manifold through toSpace, and so do the charts of a simple normal crossings divisor set (IsSncDivisorSet).

theorem AnalyticSpace.exists_localModel_ofManifold {K : Type} [RCLike K] {E : Type u_1} [NormedAddCommGroup E] [NormedSpace K E] {n : ℕ} (ψ : E ≃L[K] Fin n → K) (M : Type u) [TopologicalSpace M] [ChartedSpace E M] [IsManifold (modelWithCornersSelf K E) ⊤ M] (x : M) :
∃ (U : TopologicalSpace.Opens M) (_ : x ∈ U) (n' : ℕ) (k : ℕ) (G : TopologicalSpace.Opens (Kn K n')) (f : Fin k → AnalyticFun K n' G) (W : TopologicalSpace.Opens ↑↑(localModel K n' G f).toPresheafedSpace), Nonempty (((KLocallyRingedSpace.ofManifold K E M).restrictOpen U).KIso ((localModel K n' G f).restrictOpen W))

Hironaka's clause (i) for the space of a manifold [Hir64, Ch. 0, §1, p. 120]: every point has a chart domain U such that Sp(M) | U is K-isomorphic to a local analytic K-space, namely the open ψ(φ.target) of Kⁿ with no equations, restricted to its open subspace ⊤.

noncomputable def AnalyticSpace.toSpace {K : Type} [RCLike K] {E : Type u_1} [NormedAddCommGroup E] [NormedSpace K E] {n : ℕ} (ψ : E ≃L[K] Fin n → K) (M : AnalyticManifold K E) :

The analytic K-space Sp(M) of an analytic manifold M [Hir64, Ch. 0, §1, pp. 119–120]: the K-local-ringed space (M, 𝒪_M) of analytic functions with Hironaka's clauses (i)–(iii) (see the module docstring). The coordinates ψ enter only the proofs of clauses (i) and (ii).

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    noncomputable def AnalyticSpace.toSpaceHom {K : Type} [RCLike K] {E : Type u_1} [NormedAddCommGroup E] [NormedSpace K E] {n : ℕ} (ψ : E ≃L[K] Fin n → K) {M N : AnalyticManifold K E} (f : AnalyticMap M N) :
    toSpace ψ M ⟶ toSpace ψ N

    The morphism Sp(f) : Sp(M) ⟶ Sp(N) of an analytic map f : M → N between analytic manifolds: precomposition with f on sections (ofManifoldHom).

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      Closed subspaces of manifolds as analytic spaces #

      noncomputable def AnalyticManifold.IdealSheaf.toAnalyticSpace {K : Type} [RCLike K] {n : ℕ} {A : AnalyticManifold K (Fin n → K)} (J : A.IdealSheaf) :

      The closed analytic subspace Sp(A)/J of the space Sp(A) of an analytic manifold A modelled on Kⁿ, cut out by the ideal sheaf J, as an analytic K-space: closedSubspace on Sp(A) (the coordinates on Kⁿ the identity, as in IsSncDivisorSet).

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        The canonical morphism Sp(A)/J ⟶ Sp(A) of the closed subspace.

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