Definition: Model signature

For audit purposes, a model signature is the tuple

Here $S$ and $V$ are the action and designated vertices; $\mathcal{F}$ is the field content and its parity; $\mathcal{B}$ is the fixed background and gauge-fixing data; $\mathcal{R}$ is the switch or regulator family; $G$ is the inverse or response operator with its normalization; $\mathcal{O}$ is the assembled observable; $\mathcal{C}$ is the carrier or field domain; $\mathcal{T}$ is the allowed test and insertion class; and $\nu$ is the perturbative grading and truncation. An unavailable component is marked unavailable, not treated as matching another signature.