The stopped clause along the chain of Step 2.1 #
The modified first step of [Wlo09, Theorem 7.4.1] runs Step 1a "as before": the family of the
proof of [Kol07, Lemma 102] at the mark 1, read from the unmodified marked order reduction one
dimension down (bdanFamDataOne), is applied to the nonempty boundary members in turn along a
shrinking chain of relatively compact opens (step21FamAux, hfStep2FamChain; this is
[Kol07, Theorem 103, Step 2.1]). The stopped clause of ClauseTools.lean (the field
stopped_never_blownUp of BMOmodFam) must hold along that chain. This module proves it.
The core of the proof of [Kol07, Lemma 102] (BDan.coreOfListOf, coreFamOn) blows up
Z_{-1} ⊆ Eʲ, then pushes forward the lower run on S_0 = π_{-1}^{-1}(Eʲ); every centre of the
pushed-forward run lies in the strict transform of S_0, which is inside the strict transform of
the member Eʲ together with the exceptional divisor. So the centres of the core lie in the
boundary at every stage, and StoppedClause.of_forall_center_subset_support gives the stopped
clause (the predicate of the clause, present for the stop rule, is not needed when the centres lie
in the boundary); the deletion of the empty first blow-up keeps the clause
(stoppedClause_eraseEmpty).
exists_hyp_totalTransformSeqFrom_eq_strictTransformSeq,strictTransformSeq_union,strictTransformSeq_hyp_subset_support: the iterated strict transform of a member is a member of the total-transform boundary; that of a union of two sets is the union.center_support_subset_cons_of_centersIn: the centres ofcons hZ Rlie in the boundary whenZlies in a member and the centres ofRlie in the strict transforms of a subset of that member's preimage (centersIn_pushforward).BDan.coreOfListOf_transformS_stoppedClause,BDan.coreOfListOf_stoppedClause,BDan.coreFamOn_stoppedClause: the stopped clause of the core over a list (through the order clausecons_isOfOrder_of_bridgeof the core before the deletion of the empty blow-up), over an arbitrary centre and transform, and per open (the transported value ofcoreFamOn_eq_coreOfListOf).BDanFamData.StoppedClauseFam,BDanFam_stoppedClause,BMOmod.bdanFamDataOne_stoppedClauseFam: the clause for the family data of [Kol07, Lemma 102], forBD^{an}_{n,1,j}on an open (the tuning is the identity at the mark1,tuned_one,tuned_pullback), and for the data of Step 1a.ChainState.link_stoppedClause,step21FamAux_stoppedClause,BO.hfStep2FamChain_stoppedClause: one link keeps the clause (stoppedClause_shrinkAppend), the chain by induction on the member list, and the chain of Step 2.1 at its state over the openM_{n₀+1}of the assembly of Step 2.
Sources: [Kol07, Theorem 103, Step 2.1] and the proof of [Kol07, Lemma 102]; the modified first step of [Wlo09, Theorem 7.4.1]. The statements themselves are not in the sources.
The strict transforms of a member are members: at every stage the i-fold strict transform
of the member F.hyp j is a member of the total-transform boundary (the index toLex (Sum.inl …)
iterated; the member of totalTransform at inl is the strict transform of the member,
strictTransformSeq_succ).
The iterated strict transform of a union of two sets is the union (closure_union,
Set.union_sdiff_distrib, Set.preimage_union at every stage).
The iterated strict transform of a member lies in the support of the total-transform boundary
(exists_hyp_totalTransformSeqFrom_eq_strictTransformSeq).
The centres of a cons over a push-forward lie in the boundary: for a first centre
Z ⊆ F.hyp j and a succession R on its blow-up whose centres lie in the strict transforms of a
set S' ⊆ π⁻¹(F.hyp j) (CentersIn, as in centersIn_pushforward), every centre of cons hZ R
lies in the support of the total-transform boundary at its stage: at stage 0 by Z ⊆ F.hyp j; at
stage k + 1 since π⁻¹(F.hyp j) is the member's strict transform together with the exceptional
divisor (cons_totalTransformSeqFromAux_succ, strictTransformSeq_mono,
strictTransformSeq_union, strictTransformSeq_hyp_subset_support). This is the hypothesis of
StoppedClause.of_forall_center_subset_support.
The stopped clause of the core of [Kol07, Lemma 102] over a list, at the mark 1: the
centres of the core before the deletion lie in the boundary
(center_support_subset_cons_of_centersIn with Z_{-1} ⊆ Eʲ and S_0 = π_{-1}^{-1}(Eʲ),
centersIn_pushforward through pushforwardBridge), so
StoppedClause.of_forall_center_subset_support gives the clause (its predicate, present for the
stop rule, is not needed once the centres lie in the boundary), and stoppedClause_eraseEmpty
carries it through the deletion of the empty first blow-up (the order clause
cons_isOfOrder_of_bridge).
coreOfListOf_transformS_stoppedClause over an arbitrary centre and transform (a substitution,
as in coreOfListOf_isOfOrderGe).
The stopped clause of the per-open core, at the mark 1: the per-open core is the core
over the transported value on the restricted data (coreFamOn_eq_coreOfListOf), so
coreOfListOf_stoppedClause applies with the transported value's order clause
(isOfOrderGe_transportedValue), as in coreFamOn_isOfOrderGe.
The stopped clause for the family data of [Kol07, Lemma 102] (the field
stopped_never_blownUp of BMOmodFam per triple, member and relatively compact open, in the form
of the data's own clauses).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The stopped clause of BD^{an}_{n,1,j} on an open: the core's clause at the mark 1! = 1
on the tuned triple (coreFamOn_stoppedClause with bdClass_tuned_pullback_inclusion), the tuning
commuting with the restriction (tuned_pullback) and being the identity at the mark 1
(tuned_one), as in BDanFam_isOfOrder.
The stopped clause of the data of Step 1a (the family of [Kol07, Lemma 102] at the mark 1
from the unmodified marked order reduction one dimension down, bdanFamDataOne):
BDanFam_stoppedClause at m = tuningParam 1 = 1.
One link of the chain of Step 2.1 keeps the stopped clause (the analogue of the order clause
of ChainState.link): the member's value on the induced triple at the lifted range has the clause
by the data's clause, the list so far by hypothesis, and stoppedClause_shrinkAppend composes
them; the restricted triple is rewritten by pullback_inclusion_restrictLE.
The stopped clause along the chain of Step 2.1 (induction on the member list): the initial
state is the empty list, each link is ChainState.link_stoppedClause.
The stopped clause of the chain of Step 2.1 in the assembly of Step 2, at its state over the
open M_{n₀+1} (step21FamAux_stoppedClause at the canonical chain of hfStep2FamChain, from the
clause of the data d.bd₁).