and it has only one entrance, as it is surrounded by a wall or enclosed by houses on all sides, one may establish an eiruv for all of it.

The Gemara raises a question concerning this baraita: Who is the tanna who holds that an eiruv may be established for a public domain in this manner? Rav Huna, son of Rav Yehoshua, said: It is Rabbi Yehuda, as it was taught in a baraita: Furthermore, Rabbi Yehuda said: One who has two houses opposite each other on two sides of the public domain, if he chooses, he may create a private domain for himself in the public domain. He may place a ten-handbreadth high post from here, on one side, and an additional post from there, the other side. This creates symbolic walls that provide the public domain with the legal status of a private domain. Or, one may place a beam extending from here, one end of the house, and a beam from there, the other end of the house, thereby creating symbolic partitions across the width of the street. In that way, one is permitted to carry objects and place them in the area between the symbolic partitions, as he would in a private domain. The Rabbis said to him: One may not establish an eiruv in the public domain in that way.

The Master said in the baraita quoted above: And one may not establish an eiruv for half the city. Rav Pappa said: They said this only in a case where one wishes to divide the city according to its length. Generally, a city had a public domain that ran straight across it, from the entrance on one side of the city to the entrance on its other side. The baraita rules that it is prohibited to establish an eiruv separately for the residents of each side of the public domain. But if one wants to divide the city according to its width, he may establish an eiruv for half the city. This distinction is made because in the first case the public domain that runs between the two halves is used by the residents of both halves, and therefore it joins the two into a single unit; in the second case, the residents of each half use only the half of the public domain located on their side and not the half of the public domain located on the other side.

The Gemara asks: In accordance with whose opinion is this halakha? It is not in accordance with the opinion of Rabbi Akiva. As, if it were in accordance with the opinion of Rabbi Akiva, didn’t he say that a foot that is permitted in its own place prohibits carrying even in a place that is not its own? Rabbi Akiva holds the following in the case of outer and inner courtyards, in which the residents of each courtyard established their own, independent eiruv: Since the residents of the inner courtyard, who are permitted to carry in their own courtyard, may not carry in the outer courtyard despite the fact that they have rights of passage there, it is prohibited even for the residents of the outer courtyard to carry there. By the same logic, since the residents of each half of the city are prohibited to carry in the public domain of the city’s other half, despite the fact that they may travel there, it should be prohibited for everyone to carry there, and the eiruv should not be functional.

The Gemara rejects this argument: Even if you say it is in accordance with the opinion of Rabbi Akiva, Rabbi Akiva stated his opinion there only in a case of two courtyards, one farther inside than the other, as the inner courtyard has no other entrance. Since the residents of the inner courtyard have no choice but to pass through the outer courtyard, the residents of the outer courtyard deny the residents of the inner courtyard exclusive use of their own courtyard; therefore, they can impose restrictions upon them. But here, in the case of two halves of the city, these may go out through this part of the public domain on their side of the city, leading to one entrance to the city, and these may go out through this other part of the public domain, leading to the other entrance to the city. Since the residents of each half do not have to use the portion of the public domain located in the other half, they do not impose any restrictions on the residents of the other half, even if they do in fact use it.

Some say a different version of the previous discussion. Rav Pappa said: Do not say that it is only if the city is divided according to its length that one may not establish an eiruv for half the city, but if the city is divided according to its width, one may establish a separate eiruv for each half. Rather, even if the city is divided according to its width, one may not establish an eiruv for half the city.

The Gemara asks: In accordance with whose opinion is this halakha? It is in accordance with the opinion of Rabbi Akiva. The Gemara rejects this argument: Even if you say it is in accordance with the opinion of the Rabbis, it is possible that the Rabbis stated their opinion there only in the case of two courtyards, one inside the other, as the residents of the inner courtyard can close the door to the outer courtyard and use only their own courtyard. In doing so, they impose no restrictions on the residents of the outer courtyard. But here, with regard to the division of a city, are they able to move the public domain from here? Since the residents of each half cannot be prevented from using the public domain located in the other half, even the Rabbis would agree that the eiruv is ineffective.

The Master said in the previously cited baraita that an eiruv must either be established for all of it or for each alleyway separately. The Gemara asks: What is different about an eiruv for half the city, which is not permissible? The residents of each half prohibit residents of the other from carrying, due to the fact that all the residents may use both halves. Similarly, even if they establish a separate eiruv for each alleyway, the residents should still prohibit residents of the other from carrying, as residents of one alleyway commonly enter other alleyways as well.

The Gemara answers: With what are we dealing here? We are dealing with a case where the residents erected a partition at the entrance to the alleyway as an indication that they do not want to be connected to the other alleyways. And it is like that which Rav Idi bar Avin said that Rav Ḥisda said: One of the residents of an alleyway, who made a partition for his entrance to the alleyway as a sign that he does not intend to carry from his house to the alleyway, does not prohibit the other residents of the alleyway from carrying there if he does not join in their eiruv. The reason for this is that this resident has demonstrated his desire to renounce his share of the alleyway.

It was taught in the baraita: If it was originally a public city and it is still a public city, and it has only one entrance to the public domain, one may establish an eiruv for the entire city. The Gemara relates: Rabbi Zeira established an eiruv for Rabbi Ḥiyya’s city and did not leave any section of the city out of the eiruv. Abaye said to him: What is the reason that the Master acted in this manner? Why didn’t you exclude a section of the city from the eiruv, as required in a public city?

Rabbi Zeira said to Abaye: The city Elders told me that Rav Ḥiyya bar Asi used to establish an eiruv for the entire city without excluding any section of it, and I said to myself: If he would establish an eiruv for the whole city, I can learn from this that it was originally a private city and later becomes a public one. Therefore, it is permitted to establish an eiruv for the entire city.

Abaye said to him: Those same Elders told me that the reason was different: There was a particular garbage dump on one side of the public domain, which blocked one of the entrances, leaving only one entrance to the public domain. However, now that the garbage dump has been cleared away, it has two entrances, and it is therefore prohibited to establish an eiruv for the whole city without excluding a section from the eiruv. Rabbi Zeira said to him: It was not on my mind, i.e., I was unaware that this was the situation.

Rav Ami bar Adda from Harpanya raised a dilemma before Rabba: If a public domain has a ladder on one side, to allow people to scale the wall that blocks it, and an entrance on the other side, what is the halakha? Is it considered a public domain that is open on both sides? Rabba said to him that Rav said as follows: A ladder has the status of an entrance, and therefore the public domain is considered open on both sides.

Rav Naḥman said to them: Do not listen to him. Rav Adda said that Rav said as follows: A ladder has the status of an entrance in certain cases, and it has the status of a partition in other cases. It has the status of a partition in the case that we mentioned, where there is a ladder at the end of a public domain. In this case, the ladder is not considered an entrance and therefore the public domain is considered closed at that end. It has the status of an entrance in the case of a ladder between two courtyards. If the residents of the courtyards wish, they may join the two courtyards by means of the ladder and establish one eiruv; if they wish, the two courtyards may each establish a separate eiruv.

The Gemara asks: Did Rav Naḥman actually say this? Didn’t Rav Naḥman say that Shmuel said: With regard to residents of the ground floor of a courtyard and residents of a balcony, i.e., the floor above the ground floor, who forgot