Passes 4849–4856: E₆ switching code, double-sixes, and twisted ternary incidence

Exact finite graph, code, Weyl-group, orbital-algebra, and homology results continuing the 1080-cycle / 360-K₃,₃ incidence program.

The missing binary dimension is E₆

The binary incidence kernel is K=[360,36,20]₂. Its 36 minimum words are exactly the classical 36 cubic-surface double-sixes, each represented on the 27-line carrier by a K₆,₆ minus perfect matching.

K = Cut(SRG(36,20,10,12)) + ⟨σE₆⟩

The same 36 objects are explicitly the 36 projective E₆ root pairs. The full order-51840 action on the double-sixes is conjugate to the Weyl W(E₆) action on projective roots. The extra generator σE₆ is the negative-inner-product edge signing.

Exact switching coset

The nontrivial coset over the 35-dimensional cut code has exact minimum weight 120. Its complete minimum shell has

51840 / 2 = 25920

Weyl-chamber signings. The characteristic-two extension by the one-dimensional quotient is nonsplit for both PSp and PGSp.

Standalone 360-bit code

The low shell below weight 64 is A₂₀=36, A₃₈=360, A₄₀=270, A₅₄=1200, A₅₆=3240, A₅₈=2160, A₆₀=540. Its dual is

K⊥ = [360,324,3]₂

and its 1080 weight-three dual words are precisely the E₆-sign-even triangles, equivalently the binary Levi cycles. The full coordinate automorphism group of this 360-bit code has order 51840 and is the certified W(E₆) / PGSp action.

59 / 49 orbital algebra

The PSp action on the 1080 binary minima has orbital algebra dimension 59 and center dimension 15, with complex type C⁷ × M₂(C)⁴ × M₃(C)⁴ and rational center Q⁹ × Q(√−3)³. The full PGSp action has dimension 49 and center dimension 13, with complex type C⁶ × M₂(C)⁴ × M₃(C)³ and fully split rational center Q¹³.

The K₃,₃ incidence Gram is only 3A₀+A₁+A₅ in the PGSp orbital basis and is not central.

Code399 sheet symmetry is genuine

The residual S₃⁴⁵ sheet action cannot be removed by any higher intrinsic code shell because it is already a true automorphism subgroup of the full classical code. The coordinate automorphism structure is

(S₄⁴⁰⁵ × S₃¹³⁵) ⋊ (S₃⁴⁵ ⋊ PGSp(4,3)).

Breaking sheet symmetry therefore requires external placement, timing, labels, dynamics, or another structure not contained in the binary code.

Ternary bridge needs orientation

The 1080 projective Levi eight-cycles span all 64 dimensions of H₁(Levi;F₃). The 360 projective K₃,₃ weight-six witnesses span only 54 dimensions. No global choice of projective ± orientations makes the unweighted 1080×360 incidence factor linearly to their homology map.

oriented K₃,₃ double cover → H₁(Levi;F₃), rank 54

The correct PGSp-equivariant lift uses the 720-object orientation double cover with deck reversal acting by −1. Ten ternary homology dimensions remain outside the canonical K₃,₃ family.

Evidence boundary. These are exact finite root, graph, code, group, and homology statements. No physical E₆ field, particle assignment, experimental threshold, or hardware clock claim is inferred.