The gemara states the mishna follows the ruling of Rebbe concerning shvus bein hashmoshos. According to rav yitzhak the mishna is dealing with the eiruv placed on a branch which reshus status varies depending on it's height and usage by rabbim. There is no mention of Rebbi's opininion in beginning of Shabbos that a branch gets it's din according to the ikar. I realise the two rulings of Rebbe are not connected but wondered what would be Rebbe's own opinion?
abraham , london uk
Sholom Rav.
The Machlokes to which you are referring is in Makos, 12b, between Rebbi Yehudah (who goes after the branch)and the Chachamim (who goes after the tree-trunk). However the Gemara concludes that even R. Yehudah agrees that we certainly go after the tree-trunk.
From the fact that the Rambam only discusses this in Hilchos Rotze'acch and Hilchos Ma'aser Sheini - and the Shulchan Aruch not at all, it seems that it is confined to those areas of Halachah exclusively - to determine whether it is inside the T'chum or not, and does not pertain to Hilchos Shabbos - though I cannot explain why not and am not in the Inyan to clarify it at this stage.
Wishing you and yours a Kesivah va'Chasimah Tovah.
Be'Virchas Kol Tuv
Eliezer Chrysler.
I was referring to the machlokes Rebbi and Rabonon in Shabbos 4b and again in 7b - 8a where this is used to establish the "reshus" status of the nof. ( according to rashi only to consider it as 4x4 but according to tosefos 4b d"h beilan to confer the reshus of of the ikar onto the nof )
Todah rabah ,kvh"t.
Abraham
Sholom Rav.
Sorry about that. I can only agree with your observation. Consequently, it certainly seems that, according to the Rashba in Tosfos - who maintains that 'Nof Holech achar ikar' applies also in the reverse case - where the Ikar is in the R'shus ha'Rabim and the Nof in the R'shus ha'Yachid (our case in Eruvin), the Eiruv will be effective even if it is above ten Tefachim - according to Rebbi.
Once again wishing you and yours a Kesivah va'Chasimah Tovah. Be'Virchas Kol Tuv
Eliezer Chrysler.