TransportPath
plain-language theorem explainer
A discrete transport path is a map from the eight-tick index set to the eight cube vertices: one register state per tick. Anyone deriving Berry phases or CKM CP phases on the directed Gray-code cycle cites this type. It is a pure type synonym, not a proved statement.
Claim. A discrete transport path is a function $p:\{0,\ldots,7\}\to\{0,\ldots,7\}$, assigning to each tick a vertex of the $3$-cube (the eight-tick recognition register).
background
The module derives the CKM CP phase $\delta_{\mathrm{CKM}}$ from Berry phases of generation eigenstates transported around the directed eight-tick Gray-code cycle. The fundamental period is one octave of eight ticks ($\tau_0=1$ in RS-native units), forced by the T7 step of the unified forcing chain.
The cycle permutation cyclePerm advances a vertex along the Gray order: if $v$ is visited at tick $t$, the next vertex is the one at tick $t+1$. Explicitly it acts as $0\mapsto 1$, $1\mapsto 3$, $2\mapsto 6$, $3\mapsto 2$, $4\mapsto 0$, $5\mapsto 4$, $6\mapsto 7$, $7\mapsto 5$. A transport path is the discrete trajectory of a state under successive applications of that permutation.
Berry phase for generation $g$ is the sum of overlap arguments $\gamma_{\mathrm{Berry}}(g)=\sum_{t=0}^{7}\arg\langle\psi_g(t)|\psi_g(t+1)\rangle$ along such a path. The CP phase is a signed combination of the three generation Berry phases; chirality of the Gray code and directed traversal make it nonzero, while $\theta_{\mathrm{QCD}}$ is driven to zero by $J$-cost minimization.
proof idea
Pure definitional abbreviation: the type of transport paths is identified with functions $\mathrm{Fin},8\to\mathrm{Fin},8$. No proof obligations, tactics, or lemmas.
why it matters
This type is the carrier for all discrete cycle transport in the CP-phase derivation. Downstream, canonicalPath builds the standard path starting at vertex $v$ by iterating the cycle permutation: at tick $k$ the state sits at $\mathrm{cyclePerm}^k(v)$. That path feeds closed-loop lemmas, per-flip and per-cycle Berry phases, generation-dependent phases, and ultimately the nonzero raw CP phase.
In the Recognition framework it sits on the eight-tick octave (T7) and the chiral Gray-code geometry that distinguishes topological $\delta_{\mathrm{CKM}}$ from energetic $\theta_{\mathrm{QCD}}$. Without a uniform path type, the discrete Berry sum and the generation comparison cannot be stated cleanly.
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