The modified first step: the modified core commutes with local analytic isomorphisms #
The functoriality argument in the proof of [Kol07, Lemma 102] (the restriction of a smooth
surjection to the member is again a smooth surjection, and pull-back and restriction commute) for
the modified first step of [Wlo09, Theorem 7.4.1]: for a local analytic isomorphism g : N → M and
the pulled-back triple g^*T, the modified core of g^*T on a relatively compact open U' is the
modified core of T on g(U') pulled back along g|_{U'}, up to empty blow-ups. This is the
counterpart of BDan.coreFamOn_commutesWithLocalIsos without the first blow-up.
The argument, step by step:
- the stopped locus and
H⁺pull back (hplus_pullback:H⁺(g^*T) = g⁻¹(H⁺(T)), byBD.Zminus1_comap: a component ofg⁻¹(E^j)lies incosupp(g^*𝓘, 1)iff the component ofE^jit maps into lies incosupp(𝓘, 1)); - the restricted triple of
g^*Tong⁻¹(H⁺)is the pull-back of the restricted triple ofTalong the restrictiong|_{H⁺} : g⁻¹(H⁺) → H⁺(restrictedTripleModOf_isPullbackOf:pullback_inclusionMap_pullbackfor the ideal,emptyMember_comapfor the boundary), itself a local analytic isomorphism (IsClosedSubmanifold.isLocalDiffeomorph_restrictMap); - the functor
Rone dimension down commutes with it (its commutation with local isomorphisms, a hypothesis here) at the traceU' ∩ g⁻¹(H⁺), whose image is the traceg(U') ∩ H⁺(imageOpens_hplusRestrictMap_preimageOpens); - the push-forward on each open commutes with the pull-back along
g|_{U'}([Kol07, Definition 30, 30.3];PushforwardStage.pushforwardAux_pullbackat the two restriction stages, the general form ofpushforwardRestrict_pullback_restrictLE:pushforwardRestrict_pullback_restrictMap), and the deletions of empty blow-ups commute with both.
The transport from H⁺(g^*T) to the propositionally equal g⁻¹(H⁺(T)) reads the constructions
on an arbitrary closed hypersurface S with S = H⁺ (restrictedTripleModOf,
coreModOn_eq_of_eq, as coreFamOn_eq_of_eq does).
Generic tools: the per-open push-forward under a local analytic isomorphism #
The restriction g|_{g⁻¹(S)} : g⁻¹(S) → S maps the trace U' ∩ g⁻¹(S) into the trace W ∩ S
when g(U') ⊆ W.
The push-forward on each open commutes with the pull-back along a local analytic isomorphism
g|_{U'} : U' → W (g(U') ⊆ W), as in the proof of [Kol07, Lemma 102] with the push-forward of
[Kol07, Definition 30, 30.3]: pushforwardAux_pullback at the two restriction stages, the square
being g|_{U'} ∘ (U' ∩ g⁻¹(S) ⊆ U') = (W ∩ S ⊆ W) ∘ g|_{g⁻¹(S)}. The general form of
pushforwardRestrict_pullback_restrictLE.
Pull-backs of the values of a compatible family on two equal opens, along the restrictions of the same map, are equal (a substitution).
Commutation with a local analytic isomorphism #
The stopped locus and H⁺ pull back (Zminus1_comap; the functoriality argument in the
proof of [Kol07, Lemma 102]): H⁺(g^*T) = g⁻¹(H⁺(T)).
g⁻¹(H⁺) is a closed hypersurface of N (the preimage of a closed hypersurface under a local
analytic isomorphism, preimage_of_isLocalDiffeomorph).
The restriction g|_{H⁺} : g⁻¹(H⁺) → H⁺ (Kollár's h|_{E^j_Y} in the proof of
[Kol07, Lemma 102]) between the bundled hypersurfaces.
Equations
- Hironaka.Manifold.BMOmod.hplusRestrictMap T j g hg = ⋯.restrictMap ⋯ ⇑g ⋯ ⋯
Instances For
The restricted triple of g^*T on g⁻¹(H⁺) is the pull-back of the restricted triple of T
along g|_{H⁺} (pull-back and restriction commute, the proof of [Kol07, Lemma 102]): the ideal by
pullback_inclusionMap_pullback, the boundary by emptyMember_comap (the trace of the pulled-back
boundary is the pull-back of the trace, member by member).
The image under g|_{H⁺} of the trace U' ∩ g⁻¹(H⁺) is the trace g(U') ∩ H⁺.
The modified core commutes with local analytic isomorphisms (the functoriality argument in
the proof of [Kol07, Lemma 102]; [Wlo09, Theorem 7.4.1]; the counterpart of
coreFamOn_commutesWithLocalIsos without the first blow-up): the modified core of g^*T on U' is
the modified core of T on g(U') pulled back along g|_{U'}, with empty blow-ups deleted, given
that the functor R one dimension down commutes with local analytic isomorphisms.
coreModOn_commutesWithLocalIsos for the compatible family coreModFam (the shape the
alignment of the links of the maximal-contact step takes).