Proposition: Closed dependencies conflict with E7(a)

A directed dependency cycle has no well-founded linearization. For lossless classical-bit legs, a NOT rule on one leg gives no pathwise consistent bit assignment; identity rules allow multiple assignments with the same external initial data.

Proof. A topological ordering of a directed cycle would require an event to precede itself. For the classical examples, the consistency equations are respectively $x=1-x$ and $x=x$. The first has no bit-valued solution; the second has both constant bit solutions. These are statements about pathwise assignments, not about selecting a stationary marginal as a substitute for an acyclic instrument execution.