CARRYING ON AND BETWEEN ROOFS
Question (Rami bar Chama): [According to Rav, according to Chachamim,] may one transfer between his roof and a pillar [in Reshus ha'Rabim]?
Question: Does he ask about transferring from a Karmelis to Reshus ha'Yachid?! (Surely, it is forbidden! Rashi - one may not carry more than four Amos on the roof. It is like a Karmelis. The pillar is 10 tall and four wide, so it is a Reshus ha'Yachid. R. Tam - the roof is Reshus ha'Yachid (one could carry there if he made an Eruv). The pillar is a Karmelis (it is less than 10 tall).)
Answer: Amidst his sharpness [he rushed to ask, and] he was not careful [to ask about the proper scenario].
Correction: Rather, he meant to ask [about a case when there is no problem of transferring from a Karmelis to Reshus ha'Yachid, e.g.] whether one may transfer between his roof and the roof of an Achsadra (Rashi - a roof supported by four poles, without walls. It belongs to someone else. Tosfos (94a-b) - it has three walls, and few Diyurin.)
Perhaps since neither is proper for Dirah, they are like one Reshus;
Or, perhaps it is forbidden, just like from roof to roof is forbidden [because they are different Reshuyos]!
Question (Rav Bivi bar Abaye): May one transfer between his roof and a ruin (Rashi; Tosfos - the roof of a ruin)?
Rav Kahana: You ask [a question equivalent to] Rami bar Chama's question!
Rav Bivi: Do not suspect me of doing so! The Achsadra is not proper for Dirah. (It does not have four walls.) We cannot learn to a ruin which [with simple renovations] is proper for Dirah. (Rami bar Chama asked about a pillar, and the Gemara said that he should have asked about an Achsadra! Perhaps Rav Bivi bar Abaye later heard that Rami himself asked about an Achsadra - Ga'on Yakov.)
Question: Since a ruin is proper for Dirah, this is obvious! (Rashi - it is unlike a roof. Surely, it is like another Reshus! Tosfos - since a ruin is proper for Dirah, its roof is just like a roof of a house. Chachamim forbid transferring from one roof to another.)
Answer: His question depends partially on Rami's question:
If you will say that (Tosfos - the roof of) the Achsadra is not proper for Dirah [and therefore one may transfer between his roof and the Achsadra's roof], perhaps we forbid regarding a ruin, for it is proper for Dirah;
Or, since no one dwells there, it is permitted!
This question is not resolved.
(Rav): According to R. Meir, if [the heights of adjacent] roofs are within 10 Tefachim of each other, and according to Chachamim when there is an isolated roof [no roof adjoins it], one may carry on all of it [even according to R. Meir. We shall refer to the roofs in the singular, for they are like one Reshus);
(Shmuel): One may carry only within four Amos.
Question: Rav contradicts himself! (Rashi - above, he permits only four Amos because the roof is totally open to a Reshus to which it is forbidden, i.e. another roof. Also here, it is totally open to Reshus ha'Rabim! Tosfos ha'Rosh - since Rav does not say Gud Asik, the roof should be like Karmelis, for it has no Mechitzos!]
Answer: Above, the Mechitzos [between houses] are not Nikarim [on the roof, therefore Rav does not say Gud Asik]. Here, the Mechitzos (the walls of the house(s) on the outside) are Nikarim.
Question: Shmuel contradicts himself! (Above, he permits the entire roof.)
Answer: Above he permits only when each roof is at most Beis Se'atayim. Here, he forbids when the area of the roof exceeds Beis Se'atayim;
The walls below were made for the house(s), and not for [Dirah on] the roof. [Even if we consider the roof to be enclosed due to Gud Asik,] the roof is like a Karfef more than Beis Se'atayim which was not Hukaf l'Dirah, so one may carry only within four Amos.
CARRYING IN A BOAT
(Rav): One may carry anywhere within a boat;
(Shmuel): One may carry only within four Amos [if the boat is more than Beis Se'atayim].
Rav permits the entire boat because it has Mechitzos, (It is considered Hukaf l'Dirah);
Shmuel forbids, because the Mechitzos are [not for Dirah, rather, only] to keep the water out.
Version #1 (Rav Ashi) Question (R. Chiya bar Yosef, to Shmuel): Is the Halachah like you, or like Rav?
Answer (Shmuel): The Halachah follows Rav.
(R. Chiya bar Yosef): Rav agrees that if one flipped [the boat] over, one may carry [on what is now on top] only within four Amos.
Question: Why did he flip it over?
If it was in order to dwell underneath it, [this is like remaking the Mechitzos l'Shem Dirah], it should be just like a roof! (Even though the Mechitzos were l'Shem Dirah below, also above is considered Hukaf l'Dirah, and even more than Beis Se'atayim is permitted.)
Answer: He flipped it over in order to tar it.
Version #2 (Rav Acha brei d'Rava): R. Chiya bar Yosef asked [Shmuel if the Halachah follows him or Rav] regarding an Achsadra:
(Rav): One may carry anywhere in an Achsadra in a valley. (It has a roof supported on poles in the corners, but no walls);
(Shmuel): One may carry only within four Amos.
Rav permits the entire Achsadra. We say Pi Tikra Yored v'Sosem;
Shmuel permits only within four Amos. We do not say Pi Tikra Yored v'Sosem.
TRANSFERRING BETWEEN RESHUYOS WITH DIFFERENT USES
Question: According to Rav, R. Meir should permit transferring between a roof and a Chatzer! (Since one may carry anywhere on the roof, it is a proper Reshus ha'Yachid, like the Chatzer)!
Answer: He decrees not to, like the decree of R. Yitzchak bar Avdimi. (When there are two adjacent similar Reshuyos, one may not transfer between them, lest one adjust a load on a mound 10 tall and four wide (a Reshus ha'Yachid) in Reshus ha'Rabim.)
Question: According to Shmuel, Chachamim should permit transferring between a roof and a Karfef! (Rashi - both of them are more than Beis Se'atayim. Both are like Karmelis, for one may carry only within four Amos. Ri - both are at most Beis Se'atayim. A Karfef resembles a roof more than a Chatzer does, and one may transfer between a roof and a Chatzer!)
Answer (Rabah bar Ula): They decree not to, lest the roof be diminished [from Beis Se'atayim and it will be a Reshus ha'Yachid, but one will still transfer between them - Rashi. Ri - perhaps part of the roof will cave in and the roof will be used more, and it will be considered Hukaf l'Dirah, unlike the Karfef.]
Question: If so, they should also decree not to transfer between two Karfifos [above Beis Se'atayim], lest (Ri - the wall of) one of them be diminished!
Answer: If a Karfef is diminished, this will be evident [because it has real Mechitzos]. If the roof is diminished, it will not be evident. (Ri - its change in status will not be evident even to people on the roof.)