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Hironaka.Resolution.Algebraic.Wlo05.EmbeddedCP1Remaining

The invariant of the loop persists through an isolation #

The loop bedAux of Hironaka.Resolution.Algebraic.Wlo05.Embedded restarts, after the absorbing stage n, on the isolated triple (X_n, K_n : I_abs, E_n) with the remaining members — the strict transforms of the members of C not absorbed at n. The strong inductions on C.card of the statement CP6 of the embedded desingularization (Hironaka.Resolution.Algebraic.Wlo05.EmbeddedChainRelative; the loop theorem markedTransformSeq_take_eq_inf_of_protectedStates and the end identity, Hironaka.Resolution.Algebraic.Wlo05.EmbeddedCP6Loop) apply the induction hypothesis to that state, so the invariant InvCE of the loop must hold for it. Hironaka.Resolution.Algebraic.Wlo05.EmbeddedRemaining proved this under the false hypothesis ClaimKC (exists_genericPoint_isolatedMarkedIdeal_of_not_absorbed); its single use of that hypothesis was the disjointness of the strict transform of a remaining member from the absorbed ones, which is now CP1 (disjoint_strictTransformSeq_of_absorbed, Hironaka.Resolution.Algebraic.Wlo05.EmbeddedCP1Main, in the form of the truncation). This module carries that disjointness to the index form across the cast of the truncation (disjoint_strictTransformSeq_of_not_absorbed_of_cp1), restores the invariant in index form (invCE_isolated) and transports it to the form of the truncation used by the loop (invCE_isolatedTriple), as embeddedStateData_isolatedTriple transports the state of the conditional loop. The generic points are those of the proof of [Kol07, Corollary 22]; the isolation is that of the proof of [Wlo05, Theorem 4.7.1]. This is not in the literature. Used in Hironaka.Resolution.Algebraic.Wlo05.EmbeddedCP6Loop and Hironaka.Resolution.Algebraic.Wlo05.EmbeddedCPBridge.

theorem Hironaka.Resolution.disjoint_support_of_heq {Y Y' : AlgebraicGeometry.Scheme} (hY : Y = Y') {a b : Y.IdealSheafData} {a' b' : Y'.IdealSheafData} (ha : a ≍ a') (hb : b ≍ b') (hd : Disjoint a.support b.support) :

Disjointness of supports transports across a cast of the ambient scheme.

theorem Hironaka.Resolution.InvCE.of_heq {Y Y' : AlgebraicGeometry.Scheme} (hY : Y = Y') {I : Y.IdealSheafData} {E : Y.DivisorFamily} {C : Finset Y.IdealSheafData} {I' : Y'.IdealSheafData} {E' : Y'.DivisorFamily} {C' : Finset Y'.IdealSheafData} (hI : I ≍ I') (hE : E ≍ E') (hC : C ≍ C') (hinv : InvCE I' E' C') :
InvCE I E C

The invariant of the loop transports across a cast of the ambient scheme.

theorem Hironaka.Resolution.disjoint_strictTransformSeq_of_not_absorbed_of_cp1 {k : Type u} [Field k] [CharZero k] {T : MarkedTriple k} {hm : T.m = 1} {C : Finset T.X.left.IdealSheafData} {h : ∃ (n : ℕ), HasAbsorptionAt T hm C n} (hinv : InvCE T.I T.E C) {c' : T.X.left.IdealSheafData} (hc' : c' ∈ C) (hnot : ¬CenterContains (bmoOneRun T hm) c' (Nat.find h)) {c : T.X.left.IdealSheafData} (hc : c ∈ absorbed T hm C h) :

CP1 in the index form: a member not absorbed at the stage of the loop has its strict transform disjoint from every absorbed one (disjoint_strictTransformSeq_of_absorbed carried across the cast of the truncation).

theorem Hironaka.Resolution.invCE_isolated {k : Type u} [Field k] [CharZero k] {T : MarkedTriple k} {hm : T.m = 1} {C : Finset T.X.left.IdealSheafData} {h : ∃ (n : ℕ), HasAbsorptionAt T hm C n} (hinv : InvCE T.I T.E C) :

The invariant of the loop for the isolated marked ideal and the remaining members, in index form (the proof of [Kol07, Corollary 22] for the generic points).

theorem Hironaka.Resolution.invCE_isolatedTriple {k : Type u} [Field k] [CharZero k] (T : MarkedTriple k) (hm : T.m = 1) (C : Finset T.X.left.IdealSheafData) (hinv : InvCE T.I T.E C) (h : ∃ (n : ℕ), HasAbsorptionAt T hm C n) :

The invariant of the loop holds again for the isolated triple and the remaining members (the isolation of the proof of [Wlo05, Theorem 4.7.1]; the generic points of the proof of [Kol07, Corollary 22]): the strict transform of each remaining member is the reduced ideal of a generic point of the support of the isolated ideal, off the boundary, at which the isolated ideal agrees with it. Needed by the strong inductions of the loop theorem and of the end identity.