Definition: Finite typed skeleton

A finite typed skeleton $\Gamma$ consists of:

1. a finite directed acyclic graph of labelled vertices and labelled quantum or hybrid wire factors;

2. fixed finite input and output types at each vertex;

3. external input and output ports, including complete records;

4. a point $p_v=(t_v,x_v)\in {\mathbb{R}}^{1,2}$ at each vertex;

5. for every edge $v\to w$, the causal constraint

   $$t_w-t_v\ge \Vert x_w-x_v{\Vert }_2/c.$$

An edge is the identity connection on its labelled factor. Additional piecewise-linear causal connections are represented by finitely many labelled identity waypoints.

A vertex may act on several owned factors, but no quantum factor is duplicated by wiring. A reported instrument includes every outcome, including inactivity and failure flags.