
Why
𝐷
𝑟
and not
𝑟𝐷
. The shedding count is a count of joint correlation labels, not of continuous vector
components. Two embedding vectors carry
2𝐷
real parameters, but the syndrome extraction circuit does
not record parameters; it records, each round, which of the
𝐷
lattice directions each vector’s change points
along. Each independent embedding vector therefore contributes one
𝐷
-valued spatial-direction index, and
for
𝑟
independently correlated vectors the redundant sector of the coupling matrix
𝐵
sector
is labeled by their
Cartesian product,
|{1, . . . , 𝐷}
𝑟
| = 𝐷
𝑟
joint labels, each a syndrome bit that reports embedding rather than
internal structure. This is the sense in which Ref. [
1
] counted
𝐷
2
= 9
“redundant syndrome bits each round”
for a moving point defect, one per (position-direction, tangent-direction) pair; the depth-3 worldline adds a
third index for the direction of its null zigzag and the redundant block becomes
𝐷
3
; the condensate, fixed by
𝐷
basis vectors, gives
𝐷
𝐷
. The exponent counts independent directional indices, and the base is the number
of values each can take.
Two conditions carry over unchanged from Ref. [
1
]. Shedding applies only to free defects: a pinned
worldline’s vertex syndromes report internal structure, not position, and are counted. And a defect can shed
only what it has, so the shedding applies only when
dim(𝐵
sector
)
exceeds the quantity to be shed; the electron,
with
dim(𝐵) = 1
, sheds nothing and keeps
𝐶
𝑒
= 1
. The full enumeration of which candidate defects survive
all five axioms and which fail (the 𝐷
4
analog of Ref. [1]’s 25-candidate sieve) is collected in Section 13.
The remaining three axioms apply to spatial defects exactly as in Ref. [
1
], with “spatial” now meaning the
three directions orthogonal to 𝑥
0
. To fix what 𝑥
0
is, we add one new axiom.
Axiom 5 (Signature and Arrow; hypothesis H1). One coordinate
𝑥
0
of the
𝐷
4
lattice carries Lorentzian
signature. The 12 nearest-neighbor bonds with
Δ𝑥
0
= 0
are spacelike and form the
𝐷
3
sub-lattice of Ref. [
1
];
the 12 time-mixed bonds are null, carry energy and momentum between time-slices, and do not enter the
sector counts of defects whose footprint lies within a slice. The vacuum code state distinguishes the two
orientations of 𝑥
0
: it has an arrow.
Under H1 there is no symmetry to break: the signature distinguishes
𝑥
0
, and the residual symmetry of the
slice, the coordinate permutations
𝑆
3
with the point group of
𝐷
3
, is the one the framework uses. What remains
to fix is the orientation of
𝑥
0
. We model it with a condensate of link variables on the null bonds,
⟨𝑈
null
⟩ ≠ 0
,
⟨𝑈
𝑥
𝑖
⟩ = 0
; there is no bond along
(1, 0, 0, 0)
for a time-axis condensate to sit on. For gauge links the local
expectation value is gauge-dependent, so the condensate must ultimately be characterized gauge-invariantly
(Section 15.4); it is a model of the arrow, not a derivation. Its localized excitation is identified with the
Higgs (Section 12). Below the condensation scale the dispersion reads
𝜔
2
= 𝑚
2
+ 𝑐
2
𝑠
|k
𝑠
|
2
with
𝑚
set by the
condensate; Lorentzian dynamics on the foliation requires in addition the sign structure of Section 3.4, which
is open.
A candidate microscopic bias for the arrow. The axiom asserts an arrow without exhibiting the dynamics
that produces it. A candidate follows from the growth kinematics already in the framework [
3
]: the lattice is
grown, growth happens at a surface, and below that surface the checks are committed while above it they are
pending. The surface distinguishes one direction from the other three by a physical difference in what has
been verified, and a defect worldline couples asymmetrically to its two interlayer directions as a result.
The cost model, and the computation. A defect in a tetrahedral void has interlayer connections to the sheet
below and the sheet above. Hopping destroys bonds to the vertices it leaves and creates bonds to those it
reaches, and every such hop transits an octahedral void, which is an
𝑋
-check site. Creating or destroying a
bond at a vertex whose check is already committed costs a factor
𝑐
in syndrome-free probability, because an
undetermined
𝑍
entering a recorded weight-twelve check flags with probability
1 − 𝑐
; interfaces that are still
pending are free. With
𝑐 =
1
2
and the amplitude per hop
𝐴
2
= 𝑐
𝑛
𝑐
, where
𝑛
𝑐
counts committed interfaces
13