The gluing of the blowing-up: pieces and transition maps #
The blowing-up M' of M with centre Y is obtained by gluing the local blowings-up
π⁻¹(U) = V' × W over the adapted charts φ : U → V × W [BM88, Definition 4.1]. Here the
pieces are indexed by an adapted chart (φ, σ) of Y (shrunk to the universe of M)
together with a chart index i < c: the piece is the chart domain S = π_i⁻¹(ψ(φ(U))) of the
local model (blowUpChartMap), and its blow-down is β = φ⁻¹ ∘ ψ⁻¹ ∘ π_i : S → U. Two
pieces (φ, σ, i) and (φ', σ', i') are glued along the transition domain
{u ∈ S | β u ∈ U' ∧ D_{i'}(u) ≠ 0} by the transition map, the lift
(Hironaka.Manifold.BlowUp.Lift) of the coordinate change ψ ∘ φ' ∘ φ⁻¹ ∘ ψ⁻¹ from chart i
to chart i'. The transition maps commute with the blow-downs, are the identity on a piece with
itself, and satisfy the inverse and cocycle laws, every law being an instance of the uniqueness
of lifts (two continuous lifts of the same coordinate change through the same chart agree, by
density of the complement of the exceptional hyperplane) or of the cocycle of the direction
quotients.
This file builds the pieces, the transition data and their laws;
Hironaka.Manifold.BlowUp.Glued feeds them to TopCat.GlueData.mk'. The gluing is not
carried out in the source, which states the result.
The pieces #
The adapted charts of Y with their block embeddings.
Equations
- Manifold.BlowUpGlue.AdaptedChart ψ Y c = { x : OpenPartialHomeomorph M E × (Fin c ↪ Fin n) // Manifold.IsAdaptedChart ψ Y x.1 x.2 }
Instances For
The adapted charts form a small type in the universe of M: a chart is determined by its
map, its inverse and its source, and E ≃ Kⁿ.
The index type of the pieces: an adapted chart (shrunk to the universe of M) and a chart
index i < c.
Equations
Instances For
The adapted chart of a piece.
Equations
- Manifold.BlowUpGlue.pieceData j = (equivShrink (Manifold.BlowUpGlue.AdaptedChart ψ Y c)).symm j.1
Instances For
The chart of a piece.
Equations
Instances For
The block embedding of a piece.
Equations
Instances For
The chart of a piece is adapted to Y, with the piece's block indices.
The chart of a piece lies in the maximal atlas of M.
Every adapted chart with every index is a piece.
The chart map π_i of a piece.
Equations
Instances For
The chart domain π_i⁻¹(ψ(φ(U))) of a piece.
Equations
Instances For
The coordinate set of a piece is open (the preimage of an open set under the polynomial π_i).
The blow-down β = φ⁻¹ ∘ ψ⁻¹ ∘ π_i of a piece.
Equations
- Manifold.BlowUpGlue.blowDown j u = ↑(Manifold.BlowUpGlue.pieceChart j).symm (ψ.symm (Manifold.BlowUpGlue.pieceMap j u))
Instances For
For u in the piece set, ψ⁻¹(π_i u) lies in the target of the piece's chart.
The blow-down of a point of the piece set lies in the source of the piece's chart.
The blow-down commutes with the chart: ψ (φ (blowDown j u)) = π_i u (condition (2) of
[BM88, Definition 4.1], chartwise).
The blow-down of a piece is continuous on the piece set.
The transition data #
The coordinate change between the charts of two pieces.
Equations
Instances For
The domain of the coordinate change between the charts of two pieces.
Equations
Instances For
The direction quotient D_{i'} of the lift of the coordinate change from chart i of the
first piece to chart i' of the second.
Equations
- Manifold.BlowUpGlue.transDir j j' = Manifold.liftDir (Manifold.BlowUpGlue.pieceEmb j) (Manifold.BlowUpGlue.pieceEmb j') j.2 (Manifold.BlowUpGlue.pieceChange j j') j'.2
Instances For
The transition domain: the points of the first piece over the second chart whose direction
lies in chart i'.
Equations
- Manifold.BlowUpGlue.transDom j j' = Manifold.BlowUpGlue.pieceMap j ⁻¹' Manifold.BlowUpGlue.pieceChangeDom j j' ∩ {v : Fin n → 𝕜 | Manifold.BlowUpGlue.transDir j j' v ≠ 0}
Instances For
The transition map: the lift of the coordinate change to the blow-up charts.
Equations
- Manifold.BlowUpGlue.transMap j j' = Manifold.liftMap (Manifold.BlowUpGlue.pieceEmb j) (Manifold.BlowUpGlue.pieceEmb j') j.2 (Manifold.BlowUpGlue.pieceChange j j') j'.2
Instances For
The domain of the coordinate change between two pieces is open.
The coordinate change between two pieces is analytic on its domain.
The coordinate change between two pieces preserves the centre in both directions (both charts
are adapted to Y).
The transition domain lies in the piece set.
The transition domain is open.
The transition map is analytic on the transition domain.
The direction quotient of the transition is analytic where the coordinate change is defined.
The points of the first piece over the second chart.
π_i u lies in the domain of the trivial coordinate change of a piece with itself.
The transition map commutes with the chart maps: π_{i'} ∘ T = g ∘ π_i.
The transition map commutes with the blow-downs.
The transition map carries the transition domain into the target piece set.
The direction quotient of a piece with itself is 1.
The transition domain of a piece with itself is the whole piece set.
The transition map of a piece with itself is the identity.
The cocycle of the direction quotients through a third piece.
The transition map lands in the reverse transition domain: D^{-1}(T u) ≠ 0, by the cocycle
of the direction quotients through the first piece itself (D_i^{id} = 1).
The transition map carries the transition domain towards a third piece into the transition domain of the second piece towards it.
The cocycle law of the transition maps: two continuous lifts of the same coordinate change
through the same chart agree (uniqueness of lifts, eqOn_of_lift_blowUpChartMap).