N4 — First cascade level
In the canonical sieve ordering, $p = 3$ is the first dynamical level. $p = 2$ has a structurally distinct role (info / anti-info).
Statement
In the canonically-ordered Eratosthenes sieve, the prime is the first dynamical cascade level: it produces the first non-trivial transfer matrix and imposes the fundamental symmetry .
The prime has a structurally distinct role: it is the info / anti-info operator creating the GFT partition . It is active in the raw sense and carries the spin/parity dynamics, but it is not a dynamical cascade face: is .
ThéorèmePlain reading. Why does the cascade start at and not ? Because 2 first supplies parity: two channels, even/odd, info/anti-info. The first transition dynamics begins at 3, which creates the first non-trivial rule (forbidden mod-3 transitions, T1).
Why it matters
N4 justifies the special role of throughout the PT cascade. Without this distinction, one would try to include in the computation (BA5) — and obtain wrong numbers. The factor enters elsewhere: via the informational leakage that dresses to give .
It is also N4 that justifies U4 (excluding as a dynamical prime) in T0.
Proof — outline
- is infrastructure. The even/odd partition is a Boolean projection; it supplies the proto-bifurcation, but not a non-trivial cascade matrix.
- is dynamical. The transfer matrix has two distinct states () with a non-trivial elimination rule.
- Forced symmetry. has stationary distribution , hence .
Detailed proof
Part 1 — is spin infrastructure
The mod-2 sieve partitions into evens and odds . This partition is:
- Boolean: an integer is even or odd, no intermediate state.
- Without internal cascade transitions: an integer’s class is trivially determined by its last bit.
The mod-2 transfer matrix on survivors (odds) is trivial: all survivors are in the same class (1 mod 2). No inter-class dynamics — no analogue of T1.
This is what makes PT call a partition operator rather than a cascade actor. Its role appears in GFT: , where the factor 2 separates persistence from entropy.
Part 2 — is the first dynamical
The mod-3 sieve on 6-rough survivors (integers neither multiples of 2 nor of 3) gives two non-trivial classes: . The transfer matrix (theorem T1) has an explicit elimination rule: .
This is the first non-trivial transfer matrix of the sieve — the distinction between (spin/infrastructure) and (cascade) is structural.
Part 3 — The symmetry
The stationary distribution of is computed by diagonalisation: eigenvalues , stationary eigenvector . Hence weight on each class — that is the value of .
This symmetry could not emerge at (which has only one non-trivial state). It emerges at for the first time, and stays constant for all later active primes (by CRT).
Consequence: U4 exclusion in T0
T0 (BA0 closure) includes condition U4: exclusion of as a dynamical prime. N4 justifies this condition at a structural level.
This exclusion is not lost: returns at another level via the dressing of (binary channel). But its dynamical contribution is filtered out of the main cascade.
For the complete derivation, see chapter 2 of the monograph.
See also
- T0 — BA0 Closure — uses U4 ( exclusion)
- T1 — Forbidden mod-3 transitions — first dynamics example
- GFT — where appears as info/anti-info partition
- All theorems