TY - JOUR A1 - Schewe, Lars A1 - Schmidt, Martin A1 - Thürauf, Johannes T1 - Structural Properties of Feasible Bookings in the European Entry-Exit Gas Market System JF - 4OR N2 - In this work we analyze the structural properties of the set of feasible bookings in the European entry-exit gas market system. We present formal definitions of feasible bookings and then analyze properties that are important if one wants to optimize over them. Thus, we study whether the sets of feasible nominations and bookings are bounded, convex, connected, conic, and star-shaped. The results depend on the specific model of gas flow in a network. Here, we discuss a simple linear flow model with arc capacities as well as nonlinear and mixed-integer nonlinear models of passive and active networks, respectively. It turns out that the set of feasible bookings has some unintuitive properties. For instance, we show that the set is nonconvex even though only a simple linear flow model is used. KW - Gas networks KW - Booking KW - Entry-exit system KW - Convexity KW - Flow models Y1 - 2018 U6 - https://doi.org/10.1007/s10288-019-00411-3 IS - 18 SP - 197 EP - 218 ER -