The function (Territory Fn GEO-AGENT), applied to some element of geographical agent, denotes the spatial region of the earth occupied by GEO-AGENT, usually demarcated by natural or artificial boundaries. Sometimes these boundaries are determined by a political process (as in the case that GEO-AGENT is a political entity). Note that this geographical region can be fluid over time, expanding and contacting as the geographical agent's borders change. Note also that the temporal extent of (Territory Fn GEO-AGENT) is equal to the temporal extent of GEO-AGENT. So, if you want to refer to Hungary's territory in 1900, you could do so with (Territory Fn HungaryIn1900).