https://chatgpt.com/share/6ab04bd4-a344-83eb-85af-06d0c597ae1b
https://osf.io/y98bc/files/osfstorage/6ab06941f4efa22e98ebb2a7
𝕆 → G₂/SO(4) → ℍ → ℂ² 成界過程初探:4 Parameterize the quaternionic subalgebras ℍ⊂𝕆, Construct G₂-invariant metric & geodesic equation on G₂/SO(4)
Any improvements in the 8D to two 4D relationship after the above analysis? AND what further analysis direction will be most needed now?
Yes. The SU(2)/Bloch analysis changes my view of the 8D → two 4D relation quite substantially. I would now reject the simplest “8 splits into two independent 4s” picture.
The stronger formulation is:
8D contains two complementary kinds of information that become separated by world-formation: a 4D associative structural closure and a 4D phase-bearing operational interface. But the second 4D is probably not the discarded half of the first projection. It is a different reading/polarization of the admitted 4D world.
That distinction matters enormously.
1. The algebra now gives us a very clean hierarchy
Cayley–Dickson gives, as real vector spaces,
𝕆 = ℍ ⊕ ℍℓ 8 = 4 + 4
and
ℍ = ℂ ⊕ ℂj 4 = 2 + 2. (Math UCR)
So there are actually two different “two-nesses”:
Octonionic split
8 → 4 + 4
versus
Quaternionic polarization
4 → 2 + 2.
We had partly conflated them earlier.
After the SU(2) analysis, I think they should be kept rigorously separate.
2. The first 8→4 is genuine loss/selection
Write an octonionic pre-world state schematically as
Ω = q + pℓ, q,p ∈ ℍ. (1)
A structural declaration selects an associative quaternionic subalgebra:
D_S : 𝕆 → ℍ
D_S(Ω)=q. (2)
This really does suppress information.
The residual is roughly
R_S(Ω)=pℓ. (3)
More importantly, what is lost is not merely four scalar coordinates. Octonions are nonassociative, whereas quaternions are associative. Selecting ℍ therefore gives a stable associative multiplication at the cost of excluding octonionic relations that do not remain inside that chosen ℍ. (Math UCR)
So I would now characterize this as:
8D possibility → 4D admissible world
or in 成界 terminology:
possibility → closure.
This remains the strongest candidate for the 先天 layer.
3. But ℍ→ℂ² is not another dimensional reduction
This is the major improvement.
Every quaternion can be represented as a pair of complex numbers, and quaternion multiplication couples those components through complex conjugation. (Math UCR)
So
ℍ ≅ ℂ² ≅ ℝ⁴
as real vector spaces.
Nothing has been thrown away yet.
Instead, choosing
q ↦ (z₁,z₂)
amounts to choosing a complex polarization of the already admitted 4D world.
And once normalized,
|z₁|²+|z₂|²=1,
we obtain
S³ ≅ SU(2);
quotienting the common U(1) phase gives the Hopf map
S¹ → S³ → S². (MathWorld)
This is exactly the geometry we used for the Flying-Star construction.
Therefore I would no longer draw:
8D → 4D₁ or 4D₂.
I would draw:
8D → 4D structural closure → 4D operational polarization → lower-dimensional observer trace.
That is much tighter.
4. So 先天 and 後天 may occupy the same four real dimensions
This is perhaps the most important conceptual result of everything we just did.