The marked transform does not depend on the chart witnesses; order ≥ 1 on cons #
FiniteSuccession.markedTransformSeq (Hironaka/Manifold/FiniteSuccession/Basic.lean) is defined
through MarkedIdealSheaf.birationalTransform at the witnesses chartAt/codim chosen from
isMonoidal (Classical.choose), while the one-step descent lemma of
Hironaka/Resolution/Analytic/MaximalContact/OneStepDescent.lean produces the marked transform at
the list's model chart ψ and the given codimension. This module shows the two agree, because none
of the data of birationalTransform hY h ⟨J, m⟩ depends on the witnesses:
MarkedIdealSheaf.birationalTransform_congr: the ideal sheafI_Yof a closed submanifold depends only on the setY(IsClosedSubmanifold.idealSheaf_congr), hence the marked transform along one blow-downπis the same for any two witnesses(ψ, c),(ψ', c')of "Yis a closed submanifold andπis its blowing-up";FiniteSuccession.cons_markedTransformSeq_one: oncons ψ hZ Cthe first marked transform isbirationalTransform hZ (isBlowUp_blowUpπ ψ hZ) ⟨J, m⟩, the form the one-step lemma yields;isMarkedOne_cons_zero/isMarkedOne_cons_tail: the two clauses ofIsMarkedOneoncons ψ hZ C— the first centre lies incosupp J, and the tail isIsMarkedOnefor the first marked transform (the recursioncons_markedTransformSeq_succ_castSucc).
These are the bookkeeping steps of Kollár's induction "X_{i+1} = X'_{i+1}, the blow-up of the
same centre" [Kol07, Theorem 97, proof], for sequences of order ≥ m in the sense of
[Kol07, Definition 66].
The marked transform π_*^{-1}(J, m) along a blow-down π does not depend on the witnesses
(ψ, c) of "Y is a closed submanifold and π its blowing-up": its inputs are the total
transform π^*J and the exceptional ideal sheaf π^*I_Y, and I_Y depends only on the set Y
(idealSheaf_congr).
On cons ψ hZ C the marked transform at stage 1 is birationalTransform at the given
witnesses (ψ, c) and the blow-down blowUpπ ψ hZ: the chosen witnesses of isMonoidal give the
same value (birationalTransform_congr).
Stage 0 of Kollár's "Z_i^U ⊆ W_i" [Kol07, Theorem 97, proof]: if cons ψ hZ C is of order
≥ 1 for (J, 1), its first centre Z lies in cosupp J.
The later stages: if cons ψ hZ C is of order ≥ 1 for (J, 1), its tail C is of order
≥ 1 for the first marked transform (π_*^{-1}(J, 1), 1) (the recursion of the marked transforms
on the constructor form).