Let J be the set of DCs. In order to model direct distribution from PZ to
customers, PZ is defined as j0. Hence, the set of RDCs is denoted by J =
J{j0}. We denote by I the set of customers and D the set of departments.
For each d ∈ D, the set of customers located in department d ∈ D is denoted
by Id. The set of departments that can be served from j ∈ J is denoted as
Dj . All departments can be served from the CDC, that is Dj0 = D.
The set of FTL routes is denoted by Ω. We introduce Ωj and Jω ⊆ J
to denote the subset of FTL routes visiting j ∈ J and the subset of RDCs
visited by route ω ∈ Ω, respectively. An FTL route ω ∈ Ω is operated by a
homogeneous fleet of vehicles of capacity Qω.