Final assembly of lemma_6_17_vanish — wiring bricks #
The capstone composing f2a (datum-independence) + Lemma 6.14 (RepIndependence.lemma_6_14) + f2b
(the orbit decomposition regular_isometric_embedding_orbit) + f2c (hcoh/hvanish) through
OrbitVanish.Q0loc_vanish_of_datum_decomp, then the SectionSix statement-move.
This file begins with the mechanical wiring bricks — independent of the open f2a/f2c1/f2c2
mathematics, buildable now. f2b's orbit datum lives over G ⧸ N while the ambient Q0loc /
Lemma-6.14 transport is over C; the assembly reindexes the datum along e : C ≃* G ⧸ N (the
FactorSet.reindexHom/Q0loc_reindexHom bridge proved in ShapiroDeepness). These two bricks
say reindexHom distributes over sumDatum and preserves equivariance under the φ-pullback
action — the two facts needed to feed the reindexed orbit sum into the reducer.
reindexHom distributes over sumDatum (the Lemma 6.17 vanishing proof wiring): reindexing a datum sum's acting
group along φ is the sum of the reindexed per-orbit data. Both sides have the same factor set
(f is untouched by reindexHom) and the same corrections (m pre-composes φ inside each
summand), so this is definitional.
Equivariance is preserved under reindexHom (the Lemma 6.17 vanishing proof wiring): if dat is an equivariant
factor set for q over C, φ : C' →* C is a group hom, and the C'-action on V is the
φ-pullback of the C-action (hφ), then dat.reindexHom φ is an equivariant factor set for q
over C'. The factor-set clauses are inherited verbatim (f unchanged); the correction clauses
(59)/(60) transport by φ's multiplicativity and the hφ action identity.
The classifying equivalence e : C ≃* AbsGalQ2 ⧸ ker ρ #
The classifying equivalence e : C ≃* AbsGalQ2 ⧸ ker ρ (the Lemma 6.17 vanishing proof): for a surjective ρ,
the inverse of the first-isomorphism AbsGalQ2 ⧸ ker ρ ≃* C. It is what f2b's
regular_isometric_embedding_orbit consumes to give the regular module W = Fin K → RegRep (ker ρ)
its C-view (the e-pullback of the canonical G ⧸ N-action).
Equations
- GQ2.VanishClose.eOfSurj ρ hρsurj = (QuotientGroup.quotientKerEquivOfSurjective ρ.toMonoidHom hρsurj).symm
Instances For
e ∘ ρ = mk' (the Lemma 6.17 vanishing proof): the classifying equivalence sends ρ g back to its coset, so
e composed with ρ is the quotient map. This is the identity that turns the C-level reindexed
pullback into the mk' N-level orbit map (where lemma_6_15_* are stated) and supplies the
Q0loc/reducer compatibility hρW : g • w = ρ g • w on W.
The final assembly of lemma_6_17_vanish #
Compose f2a (datum-independence) + Lemma 6.14 + f2b (regular embedding) + f2c1 (hcoh_*) +
the deep-class vanishing (hvanish_cup square/free, InvolutionSplice.hvanish_involution_ker
involution) through OrbitVanish.Q0loc_vanish_of_datum_decomp. The W = Fin K → RegRep (ker ρ)
instances are letI-supplied on the base RegRep (ker ρ) (so f2c1's RegRep-instance
arguments resolve and the block module's action is the Pi-lift); RegRep's opacity blocks the
global trivial AbsGalQ2-action, so this is clean.
Out-lift of an order-2 nontrivial coset is a non-N involution mod N (the Lemma 6.17 vanishing proof wiring):
for w : AbsGalQ2 ⧸ N with w * w = 1 and w ≠ 1, the section lift Quotient.out w lies outside
N yet squares into N. The involution-position fact shared by the three Sum.inr (Sum.inl _)
orbit branches of the final assembly.
The involution orbit's inner cochain is a 2-cocycle (the Lemma 6.17 vanishing proof wiring): the evensNormFun
splice attached to an involution coset g ∉ N, g² ∈ N on the index-2 pair N ≤ N ⊔ ⟨g⟩, built
from a block cocycle shapiroCoord N β, is a Z². Discharges the Sum.inr (Sum.inl _) branch of
the hZ2 obligation.
The free orbit's inner cochain vanishes in H² (the Lemma 6.17 vanishing proof wiring): the cup product of a deep
ker ρ-block cocycle with the g-conjugate of another deep block cocycle is an H²-coboundary.
Discharges the Sum.inr (Sum.inr _) branch of the hvanish obligation.
lemma_6_17_vanish, closed downstream (the Lemma 6.17 vanishing proof): the base connecting map Q⁰loc
vanishes on the deep half, from lemma_6_17_vanish's own hypotheses plus the reciprocity datum
(R, horient) threaded per the c2c4 consumer note (the architecture review flag).
Paper-tag ledger (auto-generated by paperforge; do not edit) #
- Lemma 6.14 = ⟦lem-regularrealization⟧