§6 pushout construction, step 1 (checkpoint-F9 slice 1) #
The transgression maps of prop:simpleheaddet on the literal §7 tower:
sec7SqAux (k ↦ k²) and sec7CommAux ((k,k') ↦ [k,k']) land in the ambient
Frattini copy R = Φ(K) and descend along Φ(K) (centrality + exponent two),
so they define maps on M = K/Φ(K) — the concrete carriers for the packet
fields of minimalBlock_preheadActualCentralExtensionPushoutDataOfRawTower.
Quadratic law, equivariance, annihilation/radical: next slices
(scripts_fable/DESIGN_F9_pushout_construction.md).
Ambient group-identity lemmas (coercion-free) #
The transgression carriers #
The square of a kernel element, in the ambient Frattini copy.
Equations
- Q2Presentation.Induction.sec7SqAux chief K k = Additive.ofMul ⟨↑k ^ 2, ⋯⟩
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The commutator of two kernel elements, in the ambient Frattini copy.
Equations
- Q2Presentation.Induction.sec7CommAux chief K k k' = Additive.ofMul ⟨⁅↑k, ↑k'⁆, ⋯⟩
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Ambient centrality of the Frattini layer against K.
Ambient exponent two of the Frattini layer.
Descent of the squaring transgression along Φ(K).
Descent of the commutator transgression in the first slot.
Descent of the commutator transgression in the second slot.
Slice 2: descent to M = K/Φ(K) and the quadratic law #
The squaring transgression on M = K/Φ(K).
Equations
- Q2Presentation.Induction.sec7SqMap chief K m = Quotient.liftOn' m (Q2Presentation.Induction.sec7SqAux chief K) ⋯
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The commutator transgression on M = K/Φ(K).
Equations
- Q2Presentation.Induction.sec7CommMap chief K m m' = Quotient.liftOn₂' m m' (Q2Presentation.Induction.sec7CommAux chief K) ⋯
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The quadratic law for the squaring transgression (prop:simpleheaddet
mechanism): Sq(kk') = Comm(k',k) + Sq k + Sq k' in the abelian layer R.
Slice 3a: biadditivity and alternation of the commutator transgression #
Left additivity of the commutator transgression in the abelian layer.
Alternation of the commutator transgression.
Slice 3b: equivariance of the transgressions under ambient conjugation #
Squaring transgression intertwines ambient conjugation.
Commutator transgression intertwines ambient conjugation.
Slice 4a: the λ-composed quadratic family square λ : QuadF2 M #
Right additivity of the commutator transgression.
The Frattini layer has exponent two, additive form.
Char-2 antisymmetry of the commutator transgression.
Additive-language wrappers on M #
The squaring transgression in additive language.
Equations
- Q2Presentation.Induction.sec7SqAdd chief K m = Q2Presentation.Induction.sec7SqMap chief K (Additive.toMul m)
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The commutator transgression in additive language.
Equations
- Q2Presentation.Induction.sec7CommAdd chief K m m' = Q2Presentation.Induction.sec7CommMap chief K (Additive.toMul m) (Additive.toMul m')
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Additivity of sec7CommAdd in the left slot.
Additivity of sec7CommAdd in the right slot.
Left-zero law for the commutator transgression.
Right-zero law for the commutator transgression.
The λ-composed bundled bilinear polar form on M.
Equations
- Q2Presentation.Induction.sec7PolarBilin chief K lam = LinearMap.mk₂ (ZMod 2) (fun (m m' : Q2Presentation.Induction.towerM K) => lam (Q2Presentation.Induction.sec7CommAdd chief K m m')) ⋯ ⋯ ⋯ ⋯
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The λ-composed quadratic form square λ on M (prop:simpleheaddet):
form m ↦ λ(Sq m), polar the λ-composed commutator pairing.
Equations
- One or more equations did not get rendered due to their size.
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Slice 4b-i: S-membership reductions and conditional T-annihilation #
The genuinely-§7 content of the annihilation clause is isolated as the explicit
hypothesis KillsFrattiniInterS (an invariant character kills the Φ(K) ∩ S
layer — manuscript lem:simplehead); everything else is proven group theory.
Squares of K ∩ S-elements land in S (ambient form).
Commutators against a K ∩ S-element land in S (normality of S).
The §7 kill hypothesis (lem:simplehead content, to be supplied by the
crux residual): the character kills the ambient Φ(K) ∩ S layer.
Equations
- Q2Presentation.Induction.KillsFrattiniInterS chief K lam = ∀ (r : ↥(Q2Presentation.Induction.kernelFrattini K)), ↑r ∈ chief.lower → lam (Additive.ofMul r) = 0
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Conditional T-annihilation (prop:simpleheaddet annihilation clause):
under the kill hypothesis, the λ-composed quadratic family annihilates the
radical layer T = (K∩S)/Φ(K).
Slice 5a: the concrete prehead tower, the crux bundle, and packet assembly #
The concrete prehead tower data of the literal §7 objects.
Equations
- One or more equations did not get rendered due to their size.
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The F9 crux bundle — exactly the three genuinely-§7 facts of
prop:simpleheaddet that remain after the mechanism layer above:
phi— the equivariant quadratic refinement of the squaring transgression (manuscript l.3730–3770, the self-dual-head polarization);kill— invariant characters kill theΦ(K) ∩ Slayer (lem:simplehead);radical— the polar radical lies inT(head-nondegeneracy,lem:simplehead).
- phi : Module.Dual (ZMod 2) (towerR chief K) → towerM K →ₗ[ZMod 2] Module.Dual (ZMod 2) (towerM K)
- diagonal (lam : Module.Dual (ZMod 2) (towerR chief K)) (m : towerM K) : (sec7SquareFamily chief K lam).form m = ((self.phi lam) m) m
- polar_symm (lam : Module.Dual (ZMod 2) (towerR chief K)) (m m' : towerM K) : ((sec7SquareFamily chief K lam).polar m) m' = ((self.phi lam) m) m' + ((self.phi lam) m') m
- kill (lam : Module.Dual (ZMod 2) (towerR chief K)) : lam ≠ 0 → (∀ (c : towerC K), lam ∘ₗ ↑((towerActR chief K) c) = lam) → KillsFrattiniInterS chief K lam
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Packet assembly: the full prop:simpleheaddet pushout packet over the
concrete prehead tower, from the crux bundle plus the compiled mechanism layer.
F9 crux residual (prop:simpleheaddet, l.3730–3770 + lem:simplehead).
The three genuinely-§7 facts over the literal tower: the equivariant quadratic
refinement φ_λ of the squaring transgression (the self-dual-head polarization),
the invariant-character kill of the Φ(K) ∩ S layer, and head-nondegeneracy of
the commutator pairing. Everything else in the pushout packet is THEOREM-level
(this file): descents, the quadratic law, biadditivity/alternation/antisymmetry,
equivariance of the transgressions, sec7SquareFamily, S-membership reductions,
and conditional annihilation. Strictly smaller than the checkpoint-F8 residual
minimalBlock_preheadActualCentralExtensionPushoutDataOfRawTower, which it
replaces on the live route together with sec7_pushoutPacket_ofCrux.
The pushout packet over the concrete prehead tower, from the crux residual.
Slice F10-R2: M-level equivariance of the transgressions #
M-level equivariance of the squaring transgression: Sq(c·m) = actR c (Sq m).
Invariance of the λ-composed quadratic form for invariant λ:
q_λ(c·m) = q_λ(m).
Slice F10-R3: the manuscript-exact crux and the direct extraspecial triple #
The manuscript-exact simple-head crux (prop:simpleheaddet, l.3745–3768):
(i) the socle argument b_λ(T,M) = 0; (ii) the shear/H¹-vanishing argument
q_λ|_T = 0; (iii) head-nondegeneracy (polar radical ⊆ T). Everything else in
the extraspecial determinant interface is THEOREM-level via the polarization
construction (Quadratic.polarization) and the compiled transgression layer.
Instances For
F10 crux residual — exactly the three prop:simpleheaddet facts.
The extraspecial determinant triple, direct from the manuscript-exact crux (bypassing the pushout-packet interface): the family is the polarization of the λ-composed quadratic forms; diagonal-invariance comes from the compiled transgression equivariance; annihilation and radical re-express through the polarization laws.
Slice F11-R1: commutator equivariance and the Burnside kill #
M-level equivariance of the commutator transgression.
Invariance of the λ-composed polar form for invariant λ.
The Burnside kill: a character killing all squares and all commutators of
K kills all of R = Φ(K).
Slice F11-R2: simplicity of the head (stable-submodule dichotomy) #
Mirrors the proven chief-dichotomy skeleton of towerDualInv_zero: a C-stable
submodule W with T ≤ W ≤ M has ambient preimage J normal in Y sitting
between S and P; chief-ness forces J ⊔ S ∈ {S, P}, giving W = T or
W = ⊤. No invariance trick is needed — both cases conclude directly.
The multiplicative subgroup of M-classes lying in a submodule W.
Equations
- Q2Presentation.Induction.sec7SubmoduleGrp chief K W = { carrier := {g : Q2Presentation.Induction.towerMgrp K | Additive.ofMul g ∈ W}, mul_mem' := ⋯, one_mem' := ⋯, inv_mem' := ⋯ }
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The ambient preimage of a submodule of M inside Y.
Equations
- One or more equations did not get rendered due to their size.
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C-stability makes the ambient preimage normal in Y.
Head simplicity, upstairs form (lem:simplehead): a C-stable submodule
between T and M is T or all of M.
Slice F11-R3: the radical clause from crux-(i) alone #
The polar radical of the λ-composed form, as a submodule.
Equations
- One or more equations did not get rendered due to their size.
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The radical clause of prop:simpleheaddet, PROVEN from clause (i): if the
polar form kills T × M, the polar radical lies in T. Head simplicity forces
radical ⊔ T ∈ {T, ⊤}; in the ⊤ case the polar form vanishes identically, so
q_λ is a C-invariant linear functional, hence 0 (towerDualInv_zero), and
the Burnside kill forces λ = 0 — contradiction.
Slice F11-R4: the two-fact crux #
The two-fact simple-head crux (prop:simpleheaddet clauses (i)+(ii) only;
the radical clause is now THEOREM-level via sec7_radical_subset_T_of_polarT):
(i) the socle argument b_λ(T,M) = 0; (ii) the shear/H¹-vanishing q_λ|_T = 0.
Instances For
F11 crux residual — exactly prop:simpleheaddet (i)+(ii).
The three-fact crux, theorem-level from the two-fact crux (the radical
clause is supplied by sec7_radical_subset_T_of_polarT).
Equations
- ⋯ = ⋯
Instances For
Slice F12-a: maps with invariant image into M^∨ vanish #
A linear family of C-invariant functionals on M is zero
(pointwise towerDualInv_zero). This is the engine of the clause-(i)
trivial-filtration induction: each trivial layer of T maps into the
invariants of M^∨, which vanish.
Slice F12-c: descent along a trivial chain (abstract form) #
Given a C-equivariant family f : W →ₗ M^∨ and a finite chain
⊥ = W₀ ≤ W₁ ≤ ⋯ ≤ W_n = ⊤ of C-stable submodules with TRIVIAL layer
action (act c w − w ∈ W_i for w ∈ W_{i+1}), the family vanishes: on each
layer the image functionals become invariant modulo the inductive hypothesis,
and invariant functionals on M are zero (towerDualInv_zero).
Slice F12-d: the adjoint family on T, ready for the chain #
The polar adjoint restricted to T, as a linear family into M^∨.
Equations
- One or more equations did not get rendered due to their size.
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The restricted C-action on T (stability is proven).
Equations
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Clause (i), reduced form: given ANY finite trivial chain on T
(the F12-b construction), the polar form kills T × M.
F12-b: construction of the trivial chain on T (below_scalar transport) #
Coe law for the restricted action.
The restricted action as a monoid hom into linear automorphisms of T.
Equations
- Q2Presentation.Induction.sec7ActOnTHom chief K = { toFun := fun (c : Q2Presentation.Induction.towerC K) => Q2Presentation.Induction.sec7ActOnT chief K c, map_one' := ⋯, map_mul' := ⋯ }
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The ambient subgroup of Y attached to a submodule U ≤ M: elements of
K ∩ S whose Frattini image lies in U.
Equations
- One or more equations did not get rendered due to their size.
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Multiplicative-to-additive bridge for the conjugation action on M.
The ambient of a C-stable submodule is normal in Y.
The step lemma (all below_scalar content): a proper stable
submodule of T admits a vector of T outside it that is fixed modulo it.
The augmentation filtration in M-coordinates.
Equations
- One or more equations did not get rendered due to their size.
- Q2Presentation.Induction.sec7ChainM chief K 0 = ⊥
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Slice F12-e: crux clause (i) lowered to pure chain existence #
A finite C-stable trivial chain on T (pure finite group theory; the
manuscript source is below_scalar: all chief factors below S are trivial).
- n : ℕ
Instances For
F12-b (PROVED): the trivial chain on T exists — below_scalar
transported through the Frattini quotient via the augmentation filtration.
The final crux for leaf #1: only the shear/H¹ clause (ii) remains as manuscript-analytic content; clause (i) is THEOREM-level from the chain.
Instances For
The two-fact crux, theorem-level from the chain + clause (ii).
Equations
- ⋯ = ⋯