The cocycle of three transition data near the real points #
For three normalized transition data P_ij, P_jk, P_ik
(Hironaka.AnalyticSpace.Glue.Normalize) between the local complexifications of X | U_i, X | U_j, X | U_k, the two morphisms φ_jk ∘ φ_ij and φ_ik out of the common domain D = Ω_ij ∩ φ_ij⁻¹(Ω_jk) ∩ Ω_ik ⊆ Y_i agree on an open subset N ⊆ D containing f_i(U_i ∩ U_j ∩ U_k): the
cocycle condition holds on a neighbourhood of the real points (exists_cocycle_nhd), under the
hypothesis huniq that two morphisms out of a neighbourhood of the real points of one
complexification into another, both compatible with the structure maps f, agree near the real
points; the statement needs it. This is as in the proof of [Car57, §3, Proposition 2], where the set
on which the cocycle identity holds is an open set containing the closed subspace.
This is exists_eq_near_of_huniq applied to the composite and the direct transition, whose
compatibility with f_i, f_k and whose ranges are checked from the fields of the data.
Conventions. The range hypotheses of exists_eq_near_of_huniq (the two morphisms land in
Y_k ∖ f_k(U_k ∖ (U_i ∩ U_j ∩ U_k))) hold because the real points of every transition domain lie
over its overlap (Ωi_le, Ωj_le of each datum), transitions carry real points to real points
(toFun_e_hom_val) and only real points to real points (exists_eq_of_toFun_e_hom_eq). Basic
tools come first: composition of the inclusions of open
subspaces (restrictOpenIncl_trans), the lift of f restricted to a smaller open subset
(complexifyIncl_comp_pairLift), the pulled-back open subset P.pullOpens T ⊆ Y_i of T ⊆ Y_j
under the transition (imageOpens of the preimage in the restricted space) and
PairIso.mem_of_toFun_eq (real points of the domain lie over V). For U_i ∩ U_j ∩ U_k = ∅, N
may be empty; for j = i or k = i with the diagonal datum, the composite is the transition itself
and N = D works.
The inclusions of open subspaces compose.
The lift of f ∘ incl_V into Ω, restricted to V' ≤ V, is the lift of f ∘ incl_{V'}.
The preimage of an open subset T ⊆ Y_j under the transition, as an open subset of Y_i.
Equations
- P.pullOpens T = AnalyticSpace.KLocallyRingedSpace.imageOpens P.Ωi ((TopologicalSpace.Opens.map (↑(CategoryTheory.CategoryStruct.comp P.e.hom (Cj.Y.ofRestrict P.Ωj))).base).obj T)
Instances For
A real point of the domain lies over V.
Compatibility restricted to a smaller open #
Two complexified inclusions compose (h₁.trans h₂), followed by any g.
The lift into D ≤ Ω followed by the inclusion D ≤ Ω is the lift into Ω.
The compatibility of a datum over V', restricted to V ≤ V'.
The cocycle near the real points #
The common domain Ω_ij ∩ φ_ij⁻¹(Ω_jk) ∩ Ω_ik ⊆ Y_i of the composite and the direct
transition.
Instances For
The first factor of the composite: D ⟶ Y_j | Ω_jk.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The composite transition φ_jk ∘ φ_ij on the common domain.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The direct transition φ_ik on the common domain.
Equations
- AnalyticSpace.Glue.directTrans Pij Pjk Pik = CategoryTheory.CategoryStruct.comp (Ci.Y.restrictOpenIncl ⋯) (CategoryTheory.CategoryStruct.comp Pik.e.hom (Ck.Y.ofRestrict Pik.Ωj))
Instances For
f_i(U_i ∩ U_j ∩ U_k) lies in the common domain.
The real points of the common domain lie over U_i ∩ U_j ∩ U_k.
The direct transition is compatible with f_i, f_k on the triple overlap.
The composite transition is compatible with f_i, f_k on the triple overlap.
The direct transition sends the common domain into Y_k ∖ f_k(U_k ∖ (U_i ∩ U_j ∩ U_k)).
The composite transition sends the common domain into Y_k ∖ f_k(U_k ∖ (U_i ∩ U_j ∩ U_k)).
The cocycle near the real points. Under the uniqueness hypothesis huniq (two morphisms out
of a neighbourhood of the real points of one complexification into another, both compatible with
the structure maps, agree on a smaller such neighbourhood), the composite φ_jk ∘ φ_ij and the
direct φ_ik agree on an open subset N ⊆ D containing f_i(U_i ∩ U_j ∩ U_k).