Eruvin 73: From the Rabbi's House

How do eruvin reflect the relationships of the people joining together in the eruv? For example, students who eat out and about (literally, in the fields), and then would sleep at the rebbe's house. Does the eating place or the sleeping place determine the starting point to measure an eruv techumin? The Gemara testifies to the phenomenon of the different cases - placing the eruv where one sleeps, and likewise where one eats - suggesting that the students could have eaten in that same house, but for whatever reason didn't (suggesting that the eruv follows where you eat, even though it's a case of following where one sleeps). Which brings us to the relationship dynamic among these principle parties - does the group of people get treated as a collective, or as a bunch of individuals. To what extent is a rebbe-son relationship the same as father-son relationship? Also: The case of 5 cases - a man with 5 wives, 5 servants, and 5 courtyards that connect, and also each connect to an alleyway. Can they participate in the eruv for the courtyards and not in the one for the alleyway? Or vice versa? And what if one forgot to join the eruv? Did people need both? Was there ever a case where one needed the courtyard and didn't need the alleyway? Plus, how cycling through the topics rounds out the topics, in process, as it were.