The shrink-and-append step of a pulled-back list #
The second general law behind the compatibility clause of the principalization family: the
shrink-and-append step of the pulled-back list π^* L along j, up to empty rounds, is the step
of L along the composite π ∘ j, whenever the two appended lists correspond along the
last-stage lift of π restricted to the reading opens (pullbackLiftRestrict, the corestriction
of pullbackLiftLast π). With shrinkAppend_pullback_eraseEmpty this reduces the comparison of
the values of two disjoining lists related by a local analytic isomorphism to the commutation of
the input family with local isomorphisms (CommutesWithLocalIsos; Kollár's functoriality for
smooth morphisms [Kol07, 34.1], the pull-back of a blow-up sequence being [Kol07, 30.1]). Used by
ValueNatural.lean.
The nil case in plain variables: the pull-backs of two lists corresponding along l agree
up to empty rounds when the maps compose (eraseEmpty_pullback_eraseEmpty, pullback_comp,
pullback_congr).
The last-stage lift of π, restricted to the reading open of j through π^* L and
corestricted to the reading open of the composite π ∘ j through L
(image_pullbackLiftLast_liftRange_subset).
Equations
- L.pullbackLiftRestrict π hπ j hj e he hcomp = Hironaka.Manifold.AnalyticMap.restrictMap (L.pullbackLiftLast π hπ) ((L.pullback π hπ).liftRange j hj) (L.liftRange e he) ⋯
Instances For
The shrink-and-append step of a pulled-back list ([Kol07, 30.1; 34.1]). The step of π^* L
along j, up to empty rounds, is the step of L along π ∘ j, whenever the appended lists
correspond along the restricted last-stage lift of π (up to empty rounds). Induction on L;
the cons step is liftStep_comp.