The local resolution of a triple over an open, and its transport along an open embedding #
The value of the embedded desingularization functor bed on a triple T of the class over a
relatively compact open W is a finite blow-up sequence on M|W (the canonical embedded
desingularization of a local embedding, [Wlo09, §4, (3)⇒(4)]); the local resolution of T
over W is the closed subspace of the last stage cut out by the final strict transform of
T.I|W, with its map to Sp(W)/T.I|W (localResolutionOn, localResolutionMapOn, defined in
PieceResolution.lean, where the localResolution of a piece is their instance at the piece's
ambient triple).
For an analytic open embedding g : N → M with T' the pull-back of T and relatively compact
W' ⊆ N, W ⊆ M with g(W') ⊆ W, the value over W' is the pull-back of the value over W
along g|W', empty blow-ups erased (the commutation with smooth morphisms, [Kol07, 34.1] —
hbed's CommutesWithLocalIsos — and the family's restriction compatibility,
[Wlo09, Theorem 2.0.2(5)]), so the final strict transforms correspond under the last-stage lift
(the lift of [Kol07, Definition 30.1]; the transports of LocalResolutionRestrict.lean) and the
local resolution of T' over W' is the part of the local resolution of T over W lying over
g(W') (localResolutionHomOn, an open immersion over the restricted closed subspaces) — the
transport exists_localResolution_restrictPiece_iso of PieceRestrictResolution.lean made generic
in the open embedding, for the disjoint-union presentation of the local model
([Kol07, Proposition 37, proof]).
Not in the sources beyond the statements cited; bookkeeping.
The restricted ideal of the pulled-back triple over W' is the pull-back, along the
restricted embedding g|W' : W' → W, of the restricted ideal of T over W — both are T.I
pulled back along W' → M (pullback_pullback).
The sequence identity along an open embedding of triples ([Kol07, 34.1];
[Wlo09, Theorem 2.0.2(5)]): the value over W' is the pull-back along g|W' : W' → W of the value
over W, empty blow-ups erased — hbed's CommutesWithLocalIsos at g and U' := W' (onto the
image open g(W')), the family's restriction compatibility from g(W') up to W,
eraseEmpty_pullback_eraseEmpty and pullback_comp.
The last-stage lift along the open embedding (the lift of [Kol07, Definition 30.1]):
stageOfEq of the sequence identity, eraseEmptyLast⁻¹, pullbackLiftLast (the pattern of
liftOfLe, LocalResolutionRestrict.lean).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The lift is a local analytic isomorphism.
The lift is injective (g|W' is).
The lift lies over g|W' (stageMap_last_pullbackLiftLast,
stageMap_last_eraseEmptyLast_symm, stageMap_last_stageOfEq). Internal.
The lift lies over g: the ambient point of the image is g of the ambient point.
The range of the lift is the part of the last stage over g(W') (range_pullbackLiftLast).
Internal.
The final strict transforms correspond under the lift
(strictTransformSubspaceSeq_last_of_eq_pullback_eraseEmpty).
The morphism of local resolutions along an open embedding of triples (Kol07, Theorem 36,
proof): homOfPullbackEq along the lift.
Equations
- bed.localResolutionHomOn T hT W hW T' hT' g hg hpb W' hW' hle hbed = Manifold.IdealSheaf.homOfPullbackEq ⇑(bed.liftOn T hT W hW T' hT' g hg hpb W' hW' hle hbed) ⋯ ⋯
Instances For
It is an open immersion (isOpenImmersion_homOfPullbackEq_of_injective at the injective local
isomorphism liftOn).
Its range is the part of the local resolution of T over g(W')
(range_toFun_homOfPullbackEq, range_liftOn, range_restrictMap).
It lies over the restricted closed subspaces: the square of the local resolution maps
with Sp(g|W') on the closed subspaces, closed by Hom.ext_of_comp_quotientι
(quotientMap_comp_quotientι four times, the composite of the ambient maps by
stageMap_last_liftOn, ofManifoldHom_comp).