Multi-zone threshold operator

Construct a threshold operator for the full nonautonomous multi-zone transport--renewal system that extends the reduced autonomous next-generation operator framework.

Background

The paper constructs a positive compact next-generation operator only after reducing the model to a single autonomous zone with frozen environmental conditions and constant harvesting effort. It explicitly identifies the construction of an analogous threshold object for the multi-zone system as an unresolved issue. Such an operator would be needed to formulate and analyze a reproduction-number threshold directly for the coupled multi-zone model.