The clauses of the analytic main theorems on a finite succession of monoidal transformations #
The clauses of Hironaka's Main Theorem II′(N) [Hir64, p. 156] on a finite succession of monoidal
transformations U_0 ← U_1 ← ⋯ ← U_r of an analytic manifold (FiniteSuccession), in which the
analytic principalization theorems state their conclusions over each compact set. They carry the
names of the clauses of the algebraic Main Theorems II and II(N) and Corollary 1 on blow-up
sequences of schemes, whose bodies they repeat with the manifold leaf predicates. One leaf
predicate says more than its scheme namesake: the manifold IdealSheaf.IsSncBoundaryWith B D
asserts simple normal crossings of B at every point and with D at the points of D, while
the scheme IsSncBoundaryWith asserts the condition at the points of D only. So the first field
of HasSncBoundaries here also asserts simple normal crossings of every intermediate boundary.
FiniteSuccession.HasSncBoundaries S B: the boundariesE_i(S.boundarySeq B), started atE_0 = Band continued byE_{i+1} = red(σ_{i+1}⁻¹(E_i) ∪ σ_{i+1}⁻¹(D_i)), have simple normal crossings with the centres, and the last one has simple normal crossings ([Hir64, Main Theorem II′(N) (iii) and the first half of (iv)]; [Wlo09, Theorem 2.0.3 (2)]).FiniteSuccession.HasConstantPositiveOrderAlongCenters S J: the order of the weak transform ofJis a positive constant along every centre ([Hir64, Main Theorem II′(N) (ii)]).
The clauses of Włodarczyk's locally finite embedded desingularization [Wlo09, Theorem 2.0.2] on the
succession over each compact set are collected in one structure, named after the structure
EmbeddedPair.IsDesingularizedBy of the algebraic embedded desingularization on blow-up sequences
of schemes (the fields are named after the analytic notions they state):
IdealSheaf.IsDesingularizedBy I S: the closed subspace with ideal sheafIis desingularized byS([Wlo09, Theorem 2.0.2 (1)–(3), (6)]);IdealSheaf.IsLocallyFinitelyDesingularizedBy I F: the familyFis a locally finite embedded desingularization of the closed subspace with ideal sheafI([Wlo09, Theorem 2.0.2]: the mapres_{Y,M}proper and an isomorphism off the singular locus, the succession over every compact desingularizing the subspace with no empty centre and every centre of codimension at least two or in the exceptional divisor, and an exceptional divisor and a strict transform on the whole space).
The clauses of Włodarczyk's locally finite principalization [Wlo09, Theorem 2.0.3], whose value is
a compatible family of finite successions over the compact sets (ExtensionCompatibleFamily), are
collected in a structure on the family, named after Włodarczyk's term:
IdealSheaf.IsLocallyFinitelyPrincipalizedBy I F: the familyFis a locally finite principalization of the ideal sheafI([Wlo09, Theorem 2.0.3 (1)–(3)], with the properness ofprin_I).
The functorial theorems assert the existence of an assignment of a compatible family to every
input, with a property of each value and a functoriality package, as the algebraic functorial
theorems assert a blow-up sequence functor (BlowUpSequenceFunctor); they differ in the inputs.
IdealSheafPair 𝕜: the pairs(M, I)of an analytic manifoldMover𝕜on a finite-dimensional model space and an ideal sheafIwith nonzero stalks, the inputs of the principalization (Kollár's triples with an empty boundary);IdealSheafPair.pullbackis the pair(N, g^*I)over a local analytic isomorphismg : N → M.HasUnderlyingManifold C 𝕜: a typeCof inputs each with an underlying manifold on a finite-dimensional model space;CompatibleFamilyAssignment C: a compatible family for every input.IdealSheaf.IsPushforwardAlong I J τ: the ideal sheafIonMis the push-forward of the ideal sheafJonNalong the closed embedding of analytic manifoldsτ : N → M(an analytic embedding, Mathlib'sIsSmoothEmbeddingatω, with closed image):Icontains the ideal ofτ(N)andJ = τ^*I(Kollár's𝒪_X/I_X = j_*(𝒪_Y/I_Y)[Kol07, 34.3]).IdealSheafPair.CommutesWithLocalAnalyticIsomorphisms P: the last sentence of [Wlo09, Theorem 2.0.3] for local analytic isomorphisms, in its two forms — over every pair of compact sets, as the relation between two successions of [Wlo09, Theorem 3.5.1 (2)], and globally, as the lift ofg : N → Mto a unique mapg̃ : Ñ → M̃overg, a local analytic isomorphism identifyingÑwith the fibre productN ×_M M̃(the "natural lifting" of [Wlo09, Theorem 2.0.1 (3)]).IdealSheafPair.CommutesWithClosedEmbeddings P: the rest of that sentence, "embeddings of ambient varieties", read as [Kol07, Theorem 35 (5)] and [Kol07, 34.3], over every pair of compact sets.EmbeddedPair 𝕜: the pairs(M, Y)of an analytic manifold on a finite-dimensional model space and a reduced closed analytic subspace, the inputs of the embedded desingularization (the analogue of the algebraicEmbeddedPair);EmbeddedPair.pullbackis the pair(N, g^{-1}(Y))over a local analytic isomorphismg : N → M.EmbeddedPair.CommutesWithLocalAnalyticIsomorphisms RandEmbeddedPair.CommutesWithClosedEmbeddings R: the two halves of [Wlo09, Theorem 2.0.2 (4)], over every pair of compact sets, the second with Kollár's hypothesis that no component of the submanifold lies in the subspace.
The boundaries E_i of the succession S started at B (S.boundarySeq B: E_0 = B and
E_{i+1} = red(σ_{i+1}⁻¹(E_i) ∪ σ_{i+1}⁻¹(D_i))) have simple normal crossings with the centres,
and the last one has simple normal crossings (Hir64, Main Theorem II′(N) (iii) and the first half
of (iv), p. 156; [Wlo09, Theorem 2.0.3 (2)]).
- isSncBoundaryWith_center (i : Fin S.length) : (S.boundarySeq B i.castSucc).IsSncBoundaryWith (S.center i)
The boundary
E_iat the stage of thei-th centre has simple normal crossings with it. - isSncBoundary_last : (S.boundarySeq B (Fin.last S.length)).IsSncBoundary
The last boundary
E_rhas simple normal crossings.
Instances For
The order of the weak transform J_i of J (S.weakTransformSeq J i) is a positive constant
along the centre D_i, for every i ([Hir64, Main Theorem II′(N) (ii), p. 156]).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The closed subspace Y of M with ideal sheaf I is desingularized by the finite
succession S : M = U_0 ← U_1 ← ⋯ ← U_r with composite σ : U_r → M
[Wlo09, Theorem 2.0.2 (1)–(3), (6)]. With exceptional divisors E_i (the boundaries
S.boundarySeq ⊤ i started at the empty boundary ⊤) and strict transforms Y_i of Y
(S.strictTransformSubspaceSeq I i), Ỹ = Y_r: the centres C_i are smooth; every E_i has
simple normal crossings with C_i and E_r has simple normal crossings; no point of a centre
lies over a point of Reg(Y) (regularLocus); the support of E_r is the preimage of
Sing(Y) = Y ∖ Reg(Y); Ỹ is smooth and has simple normal crossings with E_r; and
σ^*(I_Y) = I_Ỹ · I_Ẽ with Ẽ a combination of the components of E_r. The analogue on
manifolds of EmbeddedPair.IsDesingularizedBy on schemes.
- isNonsingular_center (i : Fin S.length) : (S.center i).IsNonsingular
The centres
C_iare smooth (Włodarczyk's "smooth closed centers"; automatic for every finite succession,FiniteSuccession.center_isNonsingular). - hasSncBoundaries : S.HasSncBoundaries ⊤
(1) Every exceptional divisor
E_ihas simple normal crossings with the centreC_i, andE_rhas simple normal crossings. - stageMap_notMem_regularLocus (i : Fin S.length) (x : ↑↧(M.finStages S.later i.castSucc).carrier) : x ∈ Manifold.IdealSheaf.support (S.center i) → (S.stageMap i.castSucc) x ∉ I.regularLocus
(2) The centres are disjoint from
Reg(Y): no point of a centreC_ilies over a point whereY(notY_i) is smooth. - support_boundarySeq_last : Manifold.IdealSheaf.support (S.boundarySeq ⊤ (Fin.last S.length)) = ⇑S.composite ⁻¹' (Manifold.IdealSheaf.support I \ I.regularLocus)
- isNonsingular_strictTransform : (S.strictTransformSubspaceSeq I (Fin.last S.length)).IsNonsingular
(3) The strict transform
Ỹ = Y_ris smooth. - isSncBoundaryTransversalTo_strictTransform : (S.boundarySeq ⊤ (Fin.last S.length)).IsSncBoundaryTransversalTo (S.strictTransformSubspaceSeq I (Fin.last S.length))
(3)
Ỹhas simple normal crossings withE_r, transversally. - isMulBoundaryMonomial_pullback : IsMulBoundaryMonomial (Manifold.IdealSheaf.pullback ⇑S.composite ⋯ I) (S.strictTransformSubspaceSeq I (Fin.last S.length)) (S.boundarySeq ⊤ (Fin.last S.length))
(6)
σ^*(I_Y) = I_Ỹ · I_Ẽ,Ẽa combination of the components ofE_rnear every point.
Instances For
The compatible family F is a locally finite principalization of the ideal sheaf I on
M [Wlo09, Theorem 2.0.3 (1)–(3)]: with prin_I = F.map : M̃ → M, and over the neighbourhood
U_K of a compact K ⊆ M the succession F.seq K : U_K = U_0 ← U_1 ← ⋯ ← U_r with composite
σ_K : U_r → U_K and exceptional divisors E_i (the boundaries (F.seq K).boundarySeq ⊤ i
started at the empty boundary ⊤): prin_I is proper; every U_K has compact closure; the
centres C_i are smooth; every E_i has simple normal crossings with C_i and E_r has simple
normal crossings; the total transform σ_K^*(I|_{U_K}) is, near every point, the ideal of an
effective combination of the components of E_r through it; the total transform prin_I^*(I) on
M̃ is a normal-crossings divisor; and prin_I is an isomorphism over the complement of the
support of I. The compatibility of the successions over two compacts is a field of
ExtensionCompatibleFamily. The analogue on manifolds of Triple.IsPrincipalizedBy on schemes,
whose fields are Kollár's clauses (1)–(3) for a single blow-up sequence.
Relation to the source.
- Translation.
I.IsLocallyFinitelyPrincipalizedBy Fsays thatFis a locally finite principalization of $I$ in the sense of [Wlo09, Theorem 2.0.3]:F.mapis $\mathrm{prin}_I \colon \tilde M \to M$; for a compact set $K$,F.nhd Kis the open neighbourhood $U \supset K$ of Włodarczyk's clause (1) andF.seq Kthe factorization $(\ast)$ of $\mathrm{prin}_I$ over $U$, whose exceptional divisors $E_{U_i}$ are the boundaries(F.seq K).boundarySeq ⊤ istarted at the empty boundary⊤; his clause (4) is the compatibility of the family (ExtensionCompatibleFamily). - Translation. The fields are the clauses of [Wlo09, Theorem 2.0.3]:
isProperMapthe properness of $\mathrm{prin}_I$,isNonsingular_centerthe smooth centres of (1),hasSncBoundariesclause (2), andisMulBoundaryMonomial_pullbackclause (3) over $U$, in whichIsMulBoundaryMonomial J ⊤ B, with the unit ideal⊤as its first factor, says that $J$ is near every point the ideal of an effective combination of the hypersurfaces of the simple normal crossings family whose reduced ideal sheaf is $B$, here $E_{U_r}$;isNormalCrossingsDivisor_pullbackis clause (3) for the total transform $\mathrm{prin}_I^*(I)$ on $\tilde M$. - Strengthening. The fields
isCompact_closure_nhdandisIsoOver_compl_supporthave no counterpart among Włodarczyk's clauses.
- isProperMap : IsProperMap ⇑F.map
prin_I : M̃ → Mis proper (the preamble of Theorem 2.0.3). - isCompact_closure_nhd (K : TopologicalSpace.Compacts M.carrier) : IsCompact (closure ↑(F.nhd K))
Every neighbourhood
U_Khas compact closure. Theng(U_K)lies in a compact for every analytic mapgout ofM, so that the commutation with local analytic isomorphisms (IdealSheafPair.CommutesWithLocalAnalyticIsomorphisms) applies to every compact ofM. - isNonsingular_center (K : TopologicalSpace.Compacts M.carrier) (i : Fin (F.seq K).length) : ((F.seq K).center i).IsNonsingular
(1) The centres
C_iare smooth (automatic for every finite succession,FiniteSuccession.center_isNonsingular). - hasSncBoundaries (K : TopologicalSpace.Compacts M.carrier) : (F.seq K).HasSncBoundaries ⊤
(2) Every exceptional divisor
E_ihas simple normal crossings with the centreC_i, andE_rhas simple normal crossings. - isMulBoundaryMonomial_pullback (K : TopologicalSpace.Compacts M.carrier) : IsMulBoundaryMonomial (Manifold.IdealSheaf.pullback ⇑(F.seq K).composite ⋯ (I.restrict (F.nhd K))) ⊤ ((F.seq K).boundarySeq ⊤ (Fin.last (F.seq K).length))
(3) The total transform
σ_K^*(I|_{U_K})is the ideal of a divisorẼ_Uwhich near every point is an effective combination of the components ofE_r(IsMulBoundaryMonomialwith the unit ideal⊤as its first factor). - isNormalCrossingsDivisor_pullback : IsNormalCrossingsDivisor (Manifold.IdealSheaf.pullback ⇑F.map ⋯ I)
(3) on
M̃: the total transformprin_I^*(I)is a normal-crossings divisor. - isIsoOver_compl_support : F.map.IsIsoOver (Manifold.IdealSheaf.support I)ᶜ
prin_Iis an isomorphism over the complement of the support ofI([Wlo09, Lemma 4.0.3]; [Kol07, Theorem 35 (3)]).
Instances For
The compatible family F is a locally finite embedded desingularization of the closed
subspace Y of M with ideal sheaf I [Wlo09, Theorem 2.0.2]: with res_{Y,M} = F.map : M̃ → M,
and over the neighbourhood U_K of a compact K ⊆ M the succession F.seq K, res_{Y,M} is
proper, it is an isomorphism over the complement of the singular locus Sing(Y) = Y ∖ Reg(Y),
every F.seq K desingularizes Y ∩ U_K (IsDesingularizedBy, clauses (1)–(3) and (6)), has
no empty centre and has every centre of codimension at least two or of codimension one inside the
exceptional divisor of its stage, and there are on M̃ an exceptional divisor E and a strict
transform Ỹ gluing the last exceptional divisors and the last strict transforms of the
successions: over every compact K, read on the last stage U_r of F.seq K through its
identification toSpace K with res_{Y,M}⁻¹(U_K), E is E_r and Ỹ is the strict transform
Y_r of Y ∩ U_K. Then E is the reduced ideal sheaf of a simple normal crossings family of
hypersurfaces of M̃ with which Ỹ has simple normal crossings, transversally, and
res_{Y,M}^*(I_Y) = I_Ỹ · I_Ẽ with Ẽ near every point an effective combination of the
components of E.
His clause (5), the compatibility of the successions over two compacts, is a field of
ExtensionCompatibleFamily.
Relation to the source.
- Translation.
I.IsLocallyFinitelyDesingularizedBy Fsays thatFis the embedded desingularization of $Y$ in the sense of [Wlo09, Theorem 2.0.2]:F.mapis $\mathrm{res}_{Y,M} \colon \tilde M \to M$, "proper bimeromorphic"; for a compact set $K$,F.nhd Kis the open subset $U$ andF.seq Kthe factorization $(\ast)$ of $\mathrm{res}_{Y,M}$ over $U$, whose clauses (1)–(3) and (6) areIsDesingularizedBy; his clause (5) is the compatibility of the family (ExtensionCompatibleFamily). - Strengthening.
isIsoOver_compl_sing, that $\mathrm{res}_{Y,M}$ is an isomorphism over $M \setminus \operatorname{Sing}(Y)$, says more than Włodarczyk's "bimeromorphic". Over $\operatorname{Reg}(Y)$ it follows from his clause (2); over $M \setminus Y$ it is not in [Wlo09, Theorem 2.0.2] but holds for his construction, an initial segment of the principalization of $I_Y$, which is an isomorphism over $M \setminus V(I_Y)$ [Wlo09, Lemma 4.0.3]. - Translation. Włodarczyk's "divisor $E$" and "strict transform $\tilde Y$" on $\tilde M$ are
the
EandYofexists_divisor_strictTransform. Its first clause identifies them over every compact with the $E_{U_r}$ and $\tilde Y \cap U_r$ of the factorization $(\ast)$: his "$\tilde Y$" and "$E$" name the global objects and their restrictions alike. Its other clauses are his clause (1) for $E$ and his clause (3) for the simple normal crossings of $\tilde Y$ with $E$, and his clause (6), $\sigma^*(I_Y) = I_{\tilde Y} I_{\tilde E}$ for $\sigma = \mathrm{res}_{Y,M}$, on $\tilde M$. - Restatement. The support of $E$, "the exceptional locus of $\mathrm{res}_{Y,M}$", and the
smoothness of $\tilde Y$ in his clause (3) are read over every compact: through the first clause
of
exists_divisor_strictTransformthey are the identity $|E_r| = \sigma_K^{-1}(\operatorname{Sing} Y)$ and the smoothness of $Y_r$ ofIsDesingularizedBy, from which $|E| = \mathrm{res}_{Y,M}^{-1}(\operatorname{Sing} Y)$ and the smoothness of $\tilde Y$ follow (IsGloballyDesingularizedBy.support_eq,IsGloballyDesingularizedBy.isNonsingular). - Translation.
center_ne_topreads the first half of Włodarczyk's Remark (2) after Theorem 2.0.3, that his centres are nonempty (the empty blow-up convention of [Kol07, 32]), andtwo_le_codim_or_boundarySeq_le_centerreads its second half, that his centres have codimension at least two, together with his Remark (1): a centre of codimension one lies in the exceptional divisor, its blow-up is an isomorphism, and it stays a component of the exceptional divisor; the centres of codimension one are not removed from the successions.
- isProperMap : IsProperMap ⇑F.map
res_{Y,M} : M̃ → Mis proper (the preamble of Theorem 2.0.2). - isIsoOver_compl_sing : F.map.IsIsoOver (Manifold.IdealSheaf.support I \ I.regularLocus)ᶜ
res_{Y,M}is an isomorphism over the complement ofSing(Y) = Y ∖ Reg(Y), more than Włodarczyk's "bimeromorphic": overReg(Y)by his clause (2), overM ∖ Yby [Wlo09, Lemma 4.0.3]. - isDesingularizedBy_seq (K : TopologicalSpace.Compacts M.carrier) : (I.restrict (F.nhd K)).IsDesingularizedBy (F.seq K)
Over the neighbourhood
U_Kof every compact, the succession desingularizesY ∩ U_K: [Wlo09, Theorem 2.0.2 (1)–(3), (6)]. - center_ne_top (K : TopologicalSpace.Compacts M.carrier) (i : Fin (F.seq K).length) : (F.seq K).center i ≠ ⊤
No centre of any succession is empty: the ideal sheaf of no centre is the unit ideal (the empty blow-up convention [Kol07, 32]; Włodarczyk's centres are nonempty, [Wlo09, Remark (2) after Theorem 2.0.3]).
- two_le_codim_or_boundarySeq_le_center (K : TopologicalSpace.Compacts M.carrier) (i : Fin (F.seq K).length) : 2 ≤ (F.seq K).codim i ∨ (F.seq K).codim i = 1 ∧ ∀ (x : ↑↧((F.seq K).stage i.castSucc).carrier), Manifold.IdealSheaf.stalkIdeal ((F.seq K).boundarySeq ⊤ i.castSucc) x ≤ Manifold.IdealSheaf.stalkIdeal ((F.seq K).center i) x
Every centre
C_ihas codimension at least two, or has codimension one and lies in the exceptional divisorE_iof its stage, the reduced ideal sheaf ofE_ilying in its ideal sheaf: then its blow-up is an isomorphism and it becomes a component of the exceptional divisor [Wlo09, Remarks (1) and (2) after Theorem 2.0.3]. - exists_divisor_strictTransform : ∃ (E_1 : F.space.IdealSheaf) (Y : F.space.IdealSheaf), (∀ (K : TopologicalSpace.Compacts M.carrier), Manifold.IdealSheaf.pullback ⇑(F.toSpace K) ⋯ E_1 = (F.seq K).boundarySeq ⊤ (Fin.last (F.seq K).length) ∧ Manifold.IdealSheaf.pullback ⇑(F.toSpace K) ⋯ Y = (F.seq K).strictTransformSubspaceSeq (I.restrict (F.nhd K)) (Fin.last (F.seq K).length)) ∧ E_1.IsSncBoundaryTransversalTo Y ∧ IsMulBoundaryMonomial (Manifold.IdealSheaf.pullback ⇑F.map ⋯ I) Y E_1
Instances For
The inputs of the functorial theorems #
A pair (M, I), the input of Włodarczyk's functorial principalization
[Wlo09, Theorem 2.0.3]: an analytic manifold M over 𝕜, modelled on a finite-dimensional space
E, with an ideal sheaf I on M with nonzero stalks (so on every connected component). Kollár's
triple (X, I, ∅) [Kol07, Notation 64] with an empty boundary, on an analytic manifold; the model
space is part of the input, so that one assignment covers the manifolds of every dimension.
- E : Type v
The model space.
- normedAddCommGroup : NormedAddCommGroup self.E
- normedSpace : NormedSpace 𝕜 self.E
- finiteDimensional : FiniteDimensional 𝕜 self.E
- M : AnalyticManifold 𝕜 self.E
The manifold.
- I : self.M.IdealSheaf
The ideal sheaf.
- isNonzeroEverywhere : Manifold.IdealSheaf.IsNonzeroEverywhere self.I
Ihas nonzero stalks.
Instances For
A type C of inputs each with an underlying analytic manifold over 𝕜, modelled on a
finite-dimensional space (the analogue of HasUnderlyingScheme for the algebraic inputs).
- model : C → Type v
The model space of the underlying manifold of an input.
- normedAddCommGroup (T : C) : NormedAddCommGroup (model T)
- normedSpace (T : C) : NormedSpace 𝕜 (model T)
- finiteDimensional (T : C) : FiniteDimensional 𝕜 (model T)
- manifold (T : C) : AnalyticManifold 𝕜 (model T)
The underlying manifold of an input.
Instances
Equations
- One or more equations did not get rendered due to their size.
A compatible family assignment on the inputs C: a compatible family of finite successions
of blow-ups (ExtensionCompatibleFamily) of the underlying manifold of every input — Włodarczyk's
prin and res as rules on all pairs, the counterpart on manifolds of a blow-up sequence functor
(BlowUpSequenceFunctor, [Kol07, Definition 31]). Its properties are the clauses of the
functorial theorems.
Equations
Instances For
The pull-back (N, g^*I) of the pair (M, I) along a local analytic isomorphism g : N → M
of manifolds modelled on E: the source of the morphism of pairs over g [Wlo09, Theorem 3.5.1].
The pulled-back ideal sheaf has nonzero stalks (IdealSheaf.isNonzeroEverywhere_comap).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The ideal sheaf I on M is the push-forward of the ideal sheaf J on N along the
closed embedding of analytic manifolds τ : N → M: τ is an analytic embedding (Mathlib's
IsSmoothEmbedding at ω: an analytic immersion, of the form u ↦ (u, 0) in suitable charts near
every point, which is a homeomorphism onto its image) with closed image, I contains the ideal of
the closed submanifold τ(N) (the vanishing ideal vanishingStalk, stalk by stalk), and
J = τ^*I. So the closed subspace of I lies in τ(N) and is the image of the closed subspace of
J. The image τ(N) is a closed submanifold of M
(IsClosedAnalyticEmbedding.exists_isClosedSubmanifold, for a finite-dimensional model) and N
carries the analytic structure induced on it: every analytic map into M with values in τ(N)
factors analytically through τ (IsClosedAnalyticEmbedding.exists_comp_eq).
Relation to the source.
- Translation. The embedding
τis Kollár's "closed embedding of smooth schemes" [Kol07, 34.3] for analytic manifolds, the embedding of Włodarczyk's "embeddings of ambient varieties" [Wlo09, Theorem 2.0.3]: $\tau$ identifies $N$ with the closed submanifold $\tau(N)$ of $M$, with its induced analytic structure. - Translation.
I.IsPushforwardAlong J τis Kollár's hypothesis on the ideal sheaves in his commutation with closed embeddings [Kol07, 34.3]: "$j \colon Y \hookrightarrow X$ is a closed embedding of smooth schemes, $0 \neq I_Y \subset \mathcal{O}_Y$ and $0 \neq I_X \subset \mathcal{O}_X$ are ideal sheaves with $\mathcal{O}_X/I_X = j_*(\mathcal{O}_Y/I_Y)$", for an empty boundary — the quotient condition being the containment of the ideal sheaf of $\tau(N)$ in $I$ with $J = \tau^* I$; the nonzero stalks are conditions on the pairs. The containment is stated stalk by stalk, the stalks of the ideal sheaf of the submanifold $\tau(N)$ being the ideals of the germs vanishing on it. - Translation. In Włodarczyk's notation,
I.IsPushforwardAlong J τsays $I = \tau_*(J) \cdot \mathcal{O}_M$, the preimage of $\tau_*(J)$ under the surjection $\mathcal{O}_M \to \tau_*(\mathcal{O}_N)$ [Wlo09, Remark (3) after Theorem 2.0.3], the ideal for which the canonical resolution of $J$ with centres $C_i$ defines that of $I$, with the centres $\tau(C_i)$ [Wlo09, Theorem 3.5.1 (3)].
- isSmoothEmbedding : Manifold.IsSmoothEmbedding (modelWithCornersSelf 𝕜 E') (modelWithCornersSelf 𝕜 E) ⊤ ⇑τ
τis an analytic embedding: an analytic immersion which is a homeomorphism onto its image. The image of
τis closed inM.- vanishingStalk_le (x : M.carrier) : Manifold.vanishingStalk (Set.range ⇑τ) x ≤ Manifold.IdealSheaf.stalkIdeal I x
J = τ^*I.
Instances For
The functoriality of an assignment on pairs #
A compatible family assignment P on the pairs (M, I) commutes with local analytic
isomorphisms, in two forms. Over every pair of compact sets: for a local analytic isomorphism
g : N → M of manifolds modelled on one space, the family P(N, g^*I) is the pull-back of
P(M, I) along g (ExtensionCompatibleFamily.IsPullbackAlong): for compacts K' ⊆ N, K ⊆ M
with g(U_{K'}) ⊆ U_K, the succession of P(N, g^*I) over U_{K'} is the pull-back along g of
the succession of P(M, I) over U_K, up to blow-ups with empty centre. Globally: writing
prin_I : M̃ → M and prin_J : Ñ → N for the maps of P(M, I) and P(N, J), J = g^*I, there is
an analytic map g̃ : Ñ → M̃ over g (prin_I ∘ g̃ = g ∘ prin_J) which is a local analytic
isomorphism, maps the fibre of prin_J over every y ∈ N bijectively onto the fibre of prin_I
over g y, and is the only continuous map Ñ → M̃ over g; the fibre bijection with the local
isomorphism is the identification of Ñ with the fibre product N ×_M M̃, stated without forming
it.
Relation to the source.
- Translation. The structure is the last sentence of [Wlo09, Theorem 2.0.3], "the morphism
$\mathrm{prin} \colon (\tilde M, \tilde I) \to (M, I)$ commutes with local analytic
isomorphisms".
isPullbackAlongis its form of [Wlo09, Theorem 3.5.1 (2)]: for a local analytic isomorphism $\varphi$, the sequence induced by $\varphi$ from the sequence of $I$ is an extension of the sequence of $\varphi^*(I)$.exists_liftis its global form, the "natural lifting" $\tilde\varphi$, "a local analytic isomorphism", of [Wlo09, Theorem 2.0.1 (3)]; the uniqueness makes the lift of a composite the composite of the lifts. - Restatement. The identification of $\tilde N$ with $N \times_M \tilde M$ of [Wlo09, Proposition 3.4.1] is stated pointwise, as the bijection of $\tilde g$ between the fibres over corresponding points; over an open set on which $g$ is injective the lift is then an analytic isomorphism between the preimages.
- Interpretation. The exact equality of [Wlo09, Theorem 3.5.1 (1)] for a surjective local analytic isomorphism has no counterpart per pair of compact sets: for $g$ the identity and compacts $K' \subsetneq K$ with a centre of the succession over $U_K$ lying over $U_K \setminus U_{K'}$, the induced succession over $U_{K'}$ has an empty centre that the succession over $U_{K'}$ omits. Its global content is read as: for surjective $g$ the lift $\tilde g$ is a surjective local analytic isomorphism identifying $\tilde N$ with $N \times_M \tilde M$.
- isPullbackAlong (T : IdealSheafPair 𝕜) {N : AnalyticManifold 𝕜 T.E} (g : AnalyticMap N T.M) (hg : IsLocalDiffeomorph (modelWithCornersSelf 𝕜 T.E) (modelWithCornersSelf 𝕜 T.E) ⊤ ⇑g) : (P (T.pullback g hg)).IsPullbackAlong (P T) g
The family
P(N, g^*I)is the pull-back ofP(M, I)alongg, over every pair of compacts. - exists_lift (T : IdealSheafPair 𝕜) {N : AnalyticManifold 𝕜 T.E} (g : AnalyticMap N T.M) (hg : IsLocalDiffeomorph (modelWithCornersSelf 𝕜 T.E) (modelWithCornersSelf 𝕜 T.E) ⊤ ⇑g) : ∃ (g' : AnalyticMap (P (T.pullback g hg)).space (P T).space), (∀ (q : (P (T.pullback g hg)).space.carrier), (P T).map (g' q) = g ((P (T.pullback g hg)).map q)) ∧ IsLocalDiffeomorph (modelWithCornersSelf 𝕜 T.E) (modelWithCornersSelf 𝕜 T.E) ⊤ ⇑g' ∧ (∀ (y : N.carrier), Set.BijOn (⇑g') (⇑(P (T.pullback g hg)).map ⁻¹' {y}) (⇑(P T).map ⁻¹' {g y})) ∧ ∀ (φ : (P (T.pullback g hg)).space.carrier → (P T).space.carrier), Continuous φ → (∀ (q : (P (T.pullback g hg)).space.carrier), (P T).map (φ q) = g ((P (T.pullback g hg)).map q)) → φ = ⇑g'
There is an analytic map
g̃ : Ñ → M̃overg, a local analytic isomorphism bijective between the fibres overyand overg y, and the only continuous map overg.
Instances For
A compatible family assignment P on the pairs (M, I) commutes with closed embeddings:
for pairs (M, I) and (N, J) and a closed embedding of analytic manifolds τ : N → M along
which I is the push-forward of J (IdealSheaf.IsPushforwardAlong: τ(N) a closed
submanifold, I ⊇ 𝓘_{τ(N)}, J = τ^*I), the family P(M, I) is the push-forward of P(N, J)
along τ (ExtensionCompatibleFamily.IsPushforwardAlong): for compacts K' ⊆ N, K ⊆ M with
τ(U_{K'}) ⊆ U_K, the succession of P(M, I) over U_K is the push-forward along τ of the
succession of P(N, J) over U_{K'}, up to blow-ups whose centres lie outside the part over
τ(U_{K'}).
Relation to the source.
- Translation.
CommutesWithClosedEmbeddings Pis the rest of the last sentence of [Wlo09, Theorem 2.0.3], "the morphism $\mathrm{prin}$ commutes with … embeddings of ambient varieties", read as Kollár's commutation with closed embeddings [Kol07, Theorem 35 (5)] in the form of [Kol07, 34.3], $B(X, I_X, E) = j_* B(Y, I_Y, E|_Y)$ for an empty $E$. - Restatement. Kollár's equation of blow-up sequences is stated over every pair of compact sets, up to blow-ups whose centres lie outside the part over $\tau(U_{K'})$, as the commutation with local analytic isomorphisms is: the succession over $U_K$ also blows up centres over $U_K \setminus \tau(U_{K'})$, which the succession over $U_{K'}$ does not see.
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Instances For
Embedded pairs #
An embedded pair (M, Y), the input of Włodarczyk's locally finite embedded
desingularization [Wlo09, Theorem 2.0.2]: an analytic manifold M over 𝕜, modelled on a
finite-dimensional space E, with a reduced closed analytic subspace Y ⊆ M, given by its ideal
sheaf (every stalk radical). The analogue on manifolds of the algebraic
AlgebraicGeometry.EmbeddedPair of Włodarczyk's embedded desingularization with smooth centres;
the model space is part of the input, as for IdealSheafPair.
- E : Type v
The model space.
- normedAddCommGroup : NormedAddCommGroup self.E
- normedSpace : NormedSpace 𝕜 self.E
- finiteDimensional : FiniteDimensional 𝕜 self.E
- M : AnalyticManifold 𝕜 self.E
The ambient manifold.
- Y : self.M.IdealSheaf
The ideal sheaf of the embedded subspace.
The embedded subspace is reduced: every stalk of its ideal sheaf is radical.
Instances For
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The pull-back (N, g^{-1}(Y)) of the embedded pair (M, Y) along a local analytic isomorphism
g : N → M of manifolds modelled on E: the source of the morphism of embedded pairs over g
[Wlo09, Theorem 3.5.1]. The pulled-back ideal sheaf is reduced
(IdealSheaf.isReduced_pullback_of_isLocalDiffeomorph).
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Instances For
The functoriality of an assignment on embedded pairs #
A compatible family assignment R on the embedded pairs (M, Y) commutes with local
analytic isomorphisms: for a local analytic isomorphism g : N → M of manifolds modelled on
one space and the embedded pair (N, g^{-1}(Y)), the family R(N, g^{-1}(Y)) is the pull-back of
R(M, Y) along g (ExtensionCompatibleFamily.IsPullbackAlong): for compacts K' ⊆ N,
K ⊆ M with g(U_{K'}) ⊆ U_K, the succession of R(N, g^{-1}(Y)) over U_{K'} is the pull-back
along g of the succession of R(M, Y) over U_K, up to blow-ups with empty centre.
Relation to the source.
- Translation.
EmbeddedPair.CommutesWithLocalAnalyticIsomorphisms Ris the first half of [Wlo09, Theorem 2.0.2 (4)], "the morphism $\mathrm{res}_{Y,M}$ … commutes with local analytic isomorphisms", in the form of [Wlo09, Theorem 3.5.1 (2)]: for a local analytic isomorphism $\varphi$, the sequence induced by $\varphi$ from the sequence of $Y$ is an extension of the sequence of $\varphi^{-1}(Y)$. - Gap. The lift of a local analytic isomorphism $g \colon N \to M$ to a map
$\tilde N \to \tilde M$ identifying $\tilde N$ with the fibre product $N \times_M \tilde M$, which
IdealSheafPair.CommutesWithLocalAnalyticIsomorphismsstates for the principalization, is not stated for the embedded desingularization, and with it the global content of the exact equality for a surjective local analytic isomorphism [Wlo09, Theorem 3.5.1 (1)], which has no counterpart per pair of compact sets.
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Instances For
A compatible family assignment R on the embedded pairs commutes with closed embeddings
of ambient manifolds: for embedded pairs (M, Y) and (N, Y') and a closed embedding of
analytic manifolds τ : N → M along which the ideal sheaf of Y is the push-forward of that of
Y' (IdealSheaf.IsPushforwardAlong: τ(N) a closed submanifold containing Y, and
Y' = τ^{-1}(Y)), such that no connected component of N lies in Y' (the ideal sheaf of Y'
has nonzero stalks), the family R(M, Y) is the push-forward of R(N, Y') along τ
(ExtensionCompatibleFamily.IsPushforwardAlong): for compacts K' ⊆ N, K ⊆ M with
τ(U_{K'}) ⊆ U_K, the succession of R(M, Y) over U_K is the push-forward along τ of the
succession of R(N, Y') over U_{K'}, up to blow-ups whose centres lie outside the part over
τ(U_{K'}).
Relation to the source.
- Translation.
EmbeddedPair.CommutesWithClosedEmbeddings Ris the second half of [Wlo09, Theorem 2.0.2 (4)], "the morphism $\mathrm{res}_{Y,M}$ … commutes with … embeddings of ambient varieties", read as Kollár's commutation with closed embeddings [Kol07, 34.3] over every pair of compact sets, asIdealSheafPair.CommutesWithClosedEmbeddingsreads the last sentence of [Wlo09, Theorem 2.0.3]: for a closed embedding $\tau \colon N \hookrightarrow M$ and a reduced $Y \subseteq N$, the embedded desingularization of $Y \subseteq M$ is the push-forward of that of $Y \subseteq N$, the stages of the succession over $N$ embedding over $\tau$ into those of the succession over $M$. - Restatement. The clause is asserted when no connected component of $N$ lies in $Y$,
Kollár's "$0 \neq I_Y$" (
T'.Y.IsNonzeroEverywhere): on such a component the embedded desingularization of $Y \subseteq N$ is trivial, while that of $Y \subseteq M$ may blow up centres on it, where other components of $Y$ meet it.
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