Step 3 of Theorem 103 in the compatible-family form: the existence statement and the descent #
of the clauses
Two consequences of the descended family functor of GlobalizeFam.lean:
AnalyticFamilyFunctor.BO_globalizeFam— Step 3 of the proof of [Kol07, Theorem 103] as an existence statement: a family functor on the classLocalMCClass mcommuting with local analytic isomorphisms extends to one onBOClass magreeing with it onLocalMCClass mand commuting with local analytic isomorphisms (witnessed byglobalizeFam).isOfOrderGe_of_agreeFam,ord_lt_of_agreeFam,indifferentToEmptyMembers_of_agreeFam— the descent of the clauses of Theorem 103 along the cover of Step 3, per relatively compact open ("the functoriality package is local", [Kol07, 104, Step 2.3]). For a relatively compact openUof a tripleTof the class, a finite coverCof the closure ofUby pieces with maximal contact (GlobalizeFamCover.lean) gives the surjective local analytic isomorphismk : ⊔ᵢ ιᵢ^{-1}(Wᵢ ∩ U) → U; for any extensionB'agreeing withBon the local class and commuting with local analytic isomorphisms, the pull-back alongkof the value ofB'onUis the value ofBon the cover (ShrunkMCCover.seqOn_coverList_eq), and the two restricted triples agree (triple_pullback_inclusion_eq). The order clause ([Kol07, Definition 66]) and the conclusionmax-ord I_r < m([Kol07, Theorem 103 (1)]) then descend along the surjectivekpointwise, and the indifference to empty boundary members descends because the triple with the smaller boundary has the same cover (maximal contact depends only on the ideal sheaf),Bis indifferent on the cover, and pull-back alongkis injective.
They give the order-reduction family assembled in BOanFamOfInput.lean its clauses.
The two restrictions agree: the restriction of the coproduct triple to the open
⊔ᵢ ιᵢ^{-1}(Wᵢ ∩ U) is the pull-back of the restriction T|_U along the cover map (both carry the
pull-back data of T along the same map ⊔ᵢ ιᵢ^{-1}(Wᵢ ∩ U) → M).
For an extension B' of B (agreeing on the local class, commuting with local analytic
isomorphisms), the value of B on the open ⊔ᵢ ιᵢ^{-1}(Wᵢ ∩ U) of the coproduct is the pull-back
of the value of B' on U along the cover map; no empty blow-up is deleted, the cover map being
onto U.
Step 3 of the proof of [Kol07, Theorem 103] in the compatible-family form, as an existence
statement: a family functor B on the class LocalMCClass m of triples with a global hypersurface
of maximal contact, commuting with local analytic isomorphisms, extends to a family functor on
BOClass m which agrees with B on LocalMCClass m and commutes with local analytic isomorphisms.
The witness is globalizeFam B hB (GlobalizeFam.lean).
The order clause ([Kol07, Definition 66]) descends along the cover of Step 3 of the proof of
[Kol07, Theorem 103], per relatively compact open: on the cover k : ⊔ᵢ ιᵢ^{-1}(Wᵢ ∩ U) → U of the
closure of U by pieces with maximal contact, the pull-back along k of the value of B' on U
is the value of B on the cover, which is of order ≥ m for the pulled-back data, and being a
smooth blow-up sequence of order ≥ m descends along a surjective local analytic isomorphism
(BlowUpSequence.isOfOrderGe_of_pullback).
The conclusion max-ord I_r < m of [Kol07, Theorem 103 (1)] descends along the cover of Step 3,
per relatively compact open: a point of the last stage over U is the image of a point of the last
stage of the pull-back along the surjective cover map k, where the value of B on the cover has
order < m, and the order of a pull-back along a local analytic isomorphism at a point is the order
at its image.
The indifference to empty boundary members descends along the cover of Step 3:
the triple with the smaller boundary has the same finite cover by pieces with maximal contact
(maximal contact depends only on the ideal sheaf), B is indifferent on the cover, and pull-back
along the surjective cover map is injective.