Explanation: The case is, the pillar is distanced from the roof four [Tefachim];

If it were close to it, the pillar would not be Reshus ha'Yachid, for it is totally breached to the roof, and it is like the roof (and permitted). However, when it is distanced, it is forbidden.

Implied question: He uses [the pillar] via above 10, which is Mekom Petur!

Answer: Even so, it is forbidden to transfer. Even the one who permits above (87b), here he agrees, since it does not rest in Mekom Petur.

Explanation #1 (Rashi): It is on top of the roof of an Achsadra of another owner. It is more than Beis Sa'atayim, so it is a Karmelis.

Observation: However, he did not want to explain inside the Achsadra. Since it is covered, it is not a Karmelis due to being more than Beis Sa'atayim, like is proven above (25a);

It says that a Karfef more than Beis Sa'atayim and he covered a Beis Se'ah (the covered part does not join to make it more than Beis Sa'atayim. Even Rabah disagrees only regarding a sloped covering.)

He asks about an Achsadra, about which it is not so relevant to say "just like residents divide below..." It does not have residents to such an extent, like Rashi explained.

Afterwards, he asks about a ruin. It is more proper for Dirah. Also regarding a ruin, he asks about the roof of the ruin, just like regarding an Achsadra.

Inference: Rashi's words connote that regarding a ruin, he does not ask about its roof, rather, about the floor of the ruin.

Explanation #2 (R. Tam): [He asks about] two Amos on a roof, which is Reshus ha'Yachid, and two Amos on a pillar that is Karmelis, for it is not 10 tall, but it is four wide. The roof is considered like Reshus ha'Yachid because Eruv helps for it to carry in all of it. It is not like other [cases of a] Karmelis.

Explanation (Rashi): Rabanan's reason is because they are adamant about different owners.

Question: Below (91b) we say that a roof, Chatzer and balcony are one Reshus according to Rabanan. This connotes even if they are of many owners!

Explanation (Rashi): R. Meir said that they are one Reshus, i.e. to carry two Amos in this one and two Amos in this one.

Implied question: (What forced him to say that he cannot carry four Amos in one?) According to the conclusion, that Shmuel establishes it when [the roof] is more than Beis Sa'atayim, this is fine. We can establish our Mishnah that it is not more than Beis Sa'atayim!

Answer: Even so, Rashi needed to explain the current Havah Amina.

Explanation: We are thinking that he discusses when the Mechitzah is not evident, for if it were evident, Shmuel would not say that he can carry only within four Amos.

Explanation: According to R. Meir, when there are many roofs we say Gud Asik only for the outer Mechitzos, since they are one Reshus, even though regarding Kelim that were Shoves in the house, they are not one Reshus, and we say Gud Asik according to Shmuel.

Question: Since according to Shmuel, the roof is considered a Karfef to forbid when it is more than Beis Sa'atayim, if so, also when it is Beis Sa'atayim or less, it should be considered like a Karfef Beis Sa'atayim that was not Hukaf l'Dirah...

... And it should be forbidden to transfer from the roof to the Chatzer according to Rabanan, just like from a Karfef to a Chatzer!

Below (91a) we say that according to Rabanan, a roof and a Chatzer are one Reshus, and Karfifos are one Reshus!

Answer: Dirah on a roof is considered Dirah more than Dirah in a Karfef, when it is not more than Beis Sa'atayim (even though when it is more, they are the same).

Explanation: We discuss when it is more than Beis Sa'atayim, like Rashi explained. They argue about whether or not the walls of the boat are considered Mukafos l'Dirah;

However, less than Beis Sa'atayim, all agree that it is a Mechitzah, and he may carry in it, for all of it becomes like four Amos, for Rav and Shmuel rule like R. Gamliel regarding a boat (above, 42b);

If even less than Beis Sa'atayim, one may carry only within four Amos, it would not be considered like four Amos, like one who was Shoves on a mound or in a cleft in a rock. [It is like four Amos] only if it is between four Amos and Beis Sa'atayim, but not if it is more than Beis Sa'atayim.

Implied suggestion: [Rav cannot hold like] R. Zeira, who said above (43a) that the walls [of a boat] are to keep out the water!

Answer: [Rav can hold like him. R. Zeira said so] only about leaving the Techum, that he may not walk in the entire boat.

Explanation: According to Shmuel according to R. Meir, we could not ask, like Rashi explained, for according to Shmuel, R. Meir considers even roofs (one is not 10 taller than the other) like Karmelis. Therefore, one may not transfer from them to the Chatzer;

Also less than Beis Sa'atayim, even though they are not Karmelis, still, since according to Shmuel they are considered not Mukaf l'Dirah, we cannot ask that he should [be allowed to] transfer from the roof to the Chatzer.

Implied question: According to Rabanan, when a roof is more than Beis Sa'atayim, one may not transfer from it to the Chatzer, and when it is less than Beis Sa'atayim, one may!

Answer: Even so, Shmuel will say that according to R. Meir a roof has the law of a Karfef, whether it is more than Beis Sa'atayim or less.

Implied question: [The Makshan] knew that R. Meir's reason for tall and low roofs [adjacent to each other] is due to R. Yitzchak bar Avdimi (one may not transfer between two adjacent similar Reshuyos, lest one adjust a load on a mound 10 tall and four wide in Reshus ha'Rabim. The same applies here!)

Answer: From a roof to a Chatzer, which are different matters, one might have thought that they are unlike a mound in Reshus ha'Rabim.

Explanation #1 (Rashi): [He asks that it should be permitted to transfer] from a roof more than Beis Sa'atayim to a Karfef more than Beis Sa'atayim, since he considers it not Mukaf l'Dirah, and both of them are Karmelis.

Question: What is [the Makshan's] source that it is forbidden?

Suggestion: It is because Rabanan say below (91a) that roofs and Chatzeros are one Reshus, and Karfifos are one Reshus.

Rejection: There, you are forced to say that they are not more than Beis Sa'atayim, like Rashi explained below. If they were more, R. Shimon would not say that a Chatzer and Karfef are one Reshus;

It is explicitly proven above (23b) regarding if the majority was seeded, that a Karfef more than Beis Sa'atayim according to R. Shimon is a Karmelis!

Explanation #2 (Ri): He asks about a roof not more than Beis Sa'atayim, that he should [be permitted to] transfer from [it to] a Karfef not more than Beis Sa'atayim, according to Rabanan;

Implied question: Dirah of a roof is more important than that of a Karfef, for it is permitted to transfer from a roof to a Chatzer, but not from a Karfef to a Chatzer!

Answer: Still, we should permit from the roof to the Karfef, because [a roof] resembles a Karfef more than [it resembles] a Chatzer, for when it is more than Beis Sa'atayim, it is a Karmelis, like a Karfef, but a Chatzer, even if it is 10 Korim (300 Sa'im), is permitted.

[Rabah bar Ula] answers that it is a decree lest it be Nifchas. I.e. perhaps the roof will cave in its middle, and people of the house will use the roof via the hole, and then the roof is considered Mukaf l'Dirah, and it is forbidden to transfer from it to the Karfef, just like from a Karfef to a Chatzer.

Implied question: [Using the roof after it caved in] is [like] Mukaf and later opened, which is not considered Mukaf l'Dirah!

Answer: Only regarding a Karfef that was not Hukaf l'Dirah, Mukaf and later opened does not help. However, for a roof, which is in any case considered slightly Mukaf l'Dirah, for one may transfer from it to a Chatzer, the hole helps to consider it totally Mukaf l'Dirah, like a Chatzer.

The Gemara asks that if so, also from a Karfef Beis Sa'atayim to a Karfef Beis Sa'atayim one should not transfer, lest it be Nifchas. I.e. perhaps one of them will be breached more than 10 [Amos], or totally, to Reshus ha'Rabim or to a valley;

Because it used the expression of Nifchas regarding the roof, it used the same expression for a breach in a Karfef (even though it is normal to say "Nifratz" regarding a breach).

[The Gemara] answers that there, if it is Nifchas, it is evident. Here, on the roof, the matter is not evident to one who stands in the Karfef, and also to one who stands on the roof, it is not evident that it is forbidden to transfer from it to the Karfef due to this hole.

Source #1: [The law of] roofs is explicit in our Mishnah, and the same applies to Chatzeros or Karfifos, since their use is the same as roofs, but not houses, which are used constantly;

Source #2: Also, just like according to Rabanan, Karfifos or Chatzeros are one Reshus, for even a roof and a Chatzer are one Reshus, and all the more so a Chatzer and a Chatzer, similarly according to R. Meir;

R. Meir argues with Rabanan only about a roof and a Chatzer, due to Rav Yitzchak bar Avdimi (who taught that if one transfers between similar Reshuyos, he may come to adjust on a mound in Reshus ha'Rabim).