at the end of the daf it says that R' Meir would agree in a certain instance if there was a daka. I do not understand. R' Meir holds that a gag has no diyurin and therefore in relationship to keilim on the gag, no eruv is needed. So why would r' meir be machmir in a case of siluk? Siluk wont make it any worse, as the heter does not come thru diyurim. to explain, we saw the siluk takes away a reshus and helps in a situation where no eruv was done. however no eruv is needed here by gag as there is no mixture of reshuyos, so how can a siluk make one asur?
Simcha
Simcha, Baruch She-Kivanta! I think your question is asked by the Chazon Ish!
The Chazon Ish writes that it seems that according to Rashi even utensils that were on the roof at the beginning of Shabbos may not be moved to other rooves. CI writes that it is not logical to say such a thing unless the scenario being discussed is one where the owner of the roof has a place to eat up there ("Makom Pita"). Otherwise siluk would not prevent him using the other rooves.
Chazon Ish continues and asks a question on Rashi; and the whole issue is not simple; but at least what we can say at the moment, Simcha, is that because of your question the CI was forced to say that since the owner of the roof eats up there, and in addition he made a dakah, this means that he has done something special to cut himself off from the other rooves, and make himself connected only to his own house, garden and roof.
KOL TUV
Dovid Bloom
Follow-up reply:
I found an answer to the above question on Rashi, in the sefer Chomat Eish, by Rav Aharon Shilo of Bnei Brak. This is in our sugya 89b, in chapter 71:6 and 71:7 of the sefer.
1) Chomat Eish explains the opinion of Rabbi Meir that one may carry from one roof to another. He cites Rashi on the Mishnah above 89a DH Kol, that since "Ein Tashmishan Tadir" on the roof; "they are not frequently used"; it follows that according to R. Meir the different rooves are not considered as different domains. He also cites the Ritva above 84b DH d'Amar Rav Nachman, who writes that a roof is different than other parts of a house, because the use of the roof is not so important for people in the courtyard. When people from the Reshut Harabim use the roof on a weekday, the residents are not particular about them doing so, and therefore one may not prevent this. Ritva writes that a chatzer or movuy is different, because the owners are particular that these areas should not be used by the public, since the chatzer and movuy are used frequently by their owners.
2) We learn from the Ritva that if an area is not frequently used, it follows that the owners are not particular about others using it. We can now say that Rashi in the Mishnah 89a, when he writes that the rooves are not frequently used, also means that for this reason the owner are not particular about this usage. This is the reason why R. Meir holds that all the rooves are one reshut, because the different owners, who live downstairs, do not care if their neighbors use all the parts of the roof upstairs.
3) We can now understand Rashi at end 89b. One of the neighbors made a wall which left his roof open to his own garden but blocked off the rooves of all other neighbors. Before he made this wall all the neighbors were together and showed that they are all equal on the roof. But now one of them has declared that he wants to go it alone. He no longer wants to be part of the roof partnership. This is what Rashi means, top 90a, that he has removed himself from the rooves. He is no longer part of the group and it follows that since he is makpid that people should not use his roof, the other neighbors will be makpid that he should not use their rooves. Therefore even R. Meir agrees that this loner's siluk prevents him from using the other rooves.
4) We see that R. Meir does not hold that a gag has no diyurin. It does have diyurin, but they do not use the roof very often so they do not mind if the neighbors use their part of the roof.
Yasher Koach
Dovid Bloom