Form1.trace — the fibrewise trace of a holomorphic 1-form (jacobian-functoriality §6) #
Unit: jacobian-functoriality. For a nonconstant holomorphic f : X → Y between Riemann surfaces
(X compact connected), the trace Tr_f η ∈ Form1 Y of η ∈ Form1 X: in the target chart at
y, its coefficient is the sum over the fibre stack at y of the repaired Jacobian-weighted
planar traces (RS.traceCoeff, TraceCoeff.lean) of η's chart coefficients, transported by
the branch/chart transition derivatives.
Main declarations:
RS.stackAt/RS.traceChart/RS.branchTrans/RS.traceCoeffFun— the coefficient data over the chart familyι := Y(preferred charts restricted to the stack neighborhoodsS.V).RS.qCoeff f η e₀ x = (deriv (e₀ ∘ f ∘ (chartAt x).symm))⁻¹ * coeffAt x η— the canonical (stack-free) per-fibre-point coefficient of the trace;RS.traceCoeffFun_eq_qSumidentifies the defining coefficient with∑ᶠ x ∈ f⁻¹{yhat}, qCoeff …away from the chart center (well- definedness), andRS.qSum_transis its chart-transition law — together these givecompaton a dense subset of each chart overlap, extended to the whole overlap by continuity (ContinuousOn.eqOn_of_subset_closure,Density.lean).RS.traceForm hf hne η : Form1 Y(viaForm1.ofCoeffs) and the challenge-facingRS.Form1.trace (f : X → Y) (hf) : Form1 X →ₗ[ℂ] Form1 Y(zero for constantf).RS.coeffAt_traceForm(the preferred-chart evaluation) andRS.coeffAt_traceForm_of_isRegularValue(the regular-value formula, feed for the projection formula / functoriality laws / the trace–period relation).
Planar helper: congruence of traceZk on the root set #
Generic chart helpers #
Chain rule for deriv through an eventual factorization (local copy of Pullback.lean's
private helper).
The two transition derivatives between overlapping maximal-atlas charts are mutually inverse.
The trace coefficient data #
The canonical fibre stack at y (a fixed choice, shared by every construction below).
Equations
- RS.stackAt hf hne y = ⋯.some
Instances For
The chart of the trace's coefficient data at index y: the preferred chart at y,
restricted to the stack neighborhood (stackAt hf hne y).V.
Equations
- RS.traceChart hf hne y = (chartAt ℂ y).restr (RS.stackAt hf hne y).V
Instances For
The transition from the preferred chart's coordinate at y to the i-th branch's target
chart coordinate.
Equations
- RS.branchTrans hf hne y i = ↑((RS.stackAt hf hne y).A i).e' ∘ ↑(chartAt ℂ y).symm
Instances For
The coefficient of the trace in the chart at index y: the branch-transported sum of the
repaired planar trace coefficients of η's stack-chart coefficients.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Analyticity of the trace coefficient on the whole (restricted) chart target — including
across branch points (the previous builder's blocker, discharged by
RS.analyticOnNhd_traceCoeff).
The canonical (stack-independent) contribution of a fibre point x to the trace's
coefficient in a target chart e₀: the coefficient of η at x, divided by the chart
derivative of f. (Junk 0 at ramified x, where the chart derivative vanishes.)
Equations
Instances For
Factorization of the chart derivative of f through a pair of adapted charts:
d(f-in-charts) = d(target transition) · (k·v^(k-1)) · d(source transition).
The per-fibre-point identity: qCoeff computed through the i-th branch of a fibre stack
is exactly the branch-transported, Jacobian-divided coefficient of η (the integrand of
traceZkForm). Holds at ramified points too (both sides junk to 0).
Well-definedness at non-center points: the defining coefficient of the trace at yhat ≠ y
(in the chart at index y) is the canonical qCoeff fibre sum over f⁻¹{yhat}.
The chart-transition law for the canonical fibre sum.
The chart-compatibility law (CC1) of the trace's coefficient data: proved on the dense
subset of the overlap avoiding the two chart centers via traceCoeffFun_eq_qSum/qSum_trans,
and extended to the whole overlap by continuity.
Assembly: traceForm and Form1.trace #
The trace's coefficient data over the chart family ι := Y.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The trace of a holomorphic 1-form along a nonconstant holomorphic map, as a raw Form1 Y.
Equations
- RS.traceForm hf hne η = RS.Form1.ofCoeffs (RS.traceData hf hne η)
Instances For
Preferred-chart evaluation of the trace: the chart at index yhat restricts the preferred
chart at yhat, so the transition factor is 1.
Pointwise additivity of the trace coefficient in η.
Pointwise ℂ-homogeneity of the trace coefficient in η.
Form1.trace (§6.1): the fibrewise trace of holomorphic 1-forms along a holomorphic
f : X → Y, as a ℂ-linear map Form1 X →ₗ[ℂ] Form1 Y. The zero map for constant f
(matching the gist's pullback convention on Jacobians).
Equations
- RS.Form1.trace f hf = if hne : ∃ (c : Y), ∀ (x : X), f x = c then 0 else { toFun := RS.traceForm hf hne, map_add' := ⋯, map_smul' := ⋯ }
Instances For
The regular-value formula #
traceCoeff at an unramified branch (k = 1, hypothesis form usable under
type-dependent k).
Regular-value evaluation of the trace: at a regular value yhat, the preferred-chart
coefficient of traceForm η is the canonical fibre sum of qCoeff (every branch is unramified
there, so the repaired coefficient evaluates literally).