
statement.
The two movements. Movement one (Sections 3–5): within the bond algebra there is no room
for charge — the commutant of the twisted color is trivial — so charge is constructed as the grading
of the twist, external to so(8) by definition, and its consequences are derived: thirds quantization,
identical charge sectors, and charge conjugation as spatial inversion. The candidate examined is
structural: charge lives in the diamond-type extension of the lattice — the glue classes of D
∗
4
/D
4
,
which is where the matter representations sit and where the companion papers place physical defects.
Movement two (Sections 6–8): the externality is an artifact of stopping at so(8). Bonds and matter
weights together are the long and short roots of F
4
; in the vacuum–matter algebra f
4
the same charge
is a Cartan coweight, triality is inner, and a second su(3) emerges whose first loaded test is passed
on the page.
Protocol. As throughout the series, the structure was computed first and compared with known
physics afterward; comparisons are labeled as comparisons. Standard background on D
4
, F
4
, triality,
and the octonions is in Refs. [4, 7, 6]; the automorphism classification is in Ref. [5]; the exceptional
Jordan route to related structures is in Ref. [11].
2 Setup
The lattice and its symmetries. The D
4
root system is the set of 24 vectors ±e
i
±e
j
, 1 ≤ i < j ≤ 4,
each of squared length 2. Its twelve spatial roots ±e
i
± e
j
with i, j ≤ 3 are the twelve FCC nearest-
neighbor bond directions of a constant-time slice. The automorphism group of the root system,
generated by reflections in the 24 roots together with reflections in the 24 short vectors ±e
i
and
(±1, ±1, ±1, ±1)/2, has order 1152, the Weyl group of F
4
; we verified this by explicit closure. It
contains 80 elements of order 3. Standard background on D
4
, its glue, and triality is in Refs. [4, 6].
Color and the twist. Fix the stacking axis (1, 1, 1). The six spatial roots orthogonal to it form
the color A
2
. Exactly two order-3 automorphisms fix this A
2
pointwise (one pair per stacking axis;
eight in all across the four axes); call one of them τ . It acts as the identity on the color plane and as
a rotation by 2π/3 on the orthogonal plane spanned by u = (1, 1, 1, 0)/
√
3 and e
4
. The 18 remaining
roots fall into six τ-orbits of three, each orbit containing one spatial and two temporal roots. The
twist is σ = Ad
e
2πi ρ·H/3
◦ τ with ρ the Weyl vector of the color A
2
; the fixed subalgebra g
0
is the
twisted su(3), of dimension 8; by the classification of finite-order automorphisms [5] the only other
candidate fixed subalgebra is G
2
, and the computed dimension excludes it (dim G
2
= 14). We verified:
no color-A
2
generator survives individually (each acquires a nontrivial phase); the eight survivors are
the two fixed Cartan directions and the six orbit sums; the orbit-sum roots are the projections of
the moved roots onto the color plane; and the Z
3
grading of so(8) under σ has dimensions (8, 10, 10).
[all reconstructed and verified]
3 No internal hypercharge, and level-3 color
Theorem 1 (No internal hypercharge) The commutant of the twisted su(3) in so(8) is trivial.
In particular no u(1) in the bond algebra commutes with color.
Proof. A Cartan direction h commutes with an orbit sum
P
i
E
α
i
only if ⟨h, α
i
⟩ is the same for
all three roots of the orbit. For h in the fixed plane this holds and h lies inside g
0
; for h with
any component in the rotated (u, e
4
) plane it fails, verified directly against all six surviving orbits.
Non-Cartan candidates are excluded by the grading: so(8) = g
0
⊕ g
1
⊕ g
2
with g
1,2
the irreducible
10 and
¯
10 of g
0
, which contain no singlets. □
2