1. Rebbi Yehudah says that two walls create a private domain.
2. The Rabanan argue that two walls are not enough to create a private domain.
3. Yerushalayim was considered a Karmelis because of its doors. What doors? Gates?
4. Some say that one can follow the opinions of Beis Shamai, just as one can follow the opinions of Beis Hillel.
5. We rule according to Beis Hillel.
A BIT MORE
1. Accordingly, if two houses across the street from each other would like to make an Eruv, they may do so by putting up a Lechi or Korah on each side of their alleyway at the end of their houses.
2. Accordingly, one is not permitted to make an Eruv in this situation (#1), because it is not permitted to make an Eruv in a public domain in this fashion.
3. Rebbi Yochanan says that if it were not for the fact that Yerushalayim had doors that were locked at night, it would have had the status of a public domain. Same question.
4. According to this opinion one should follow either all the rulings of Beis Shamai or all the rulings of Beis Hillel, whether lenient or stringent.
5. According to some opinions, this was finalized after a voice from Heaven rang out and stated that the law always follows Beis Hillel.