The opinion of the Hakhamim in the Mishna (89a) did not allow carrying from one roof to another, and Rav (ibid) explained that a person was limited to the extent that he could only carry within a four cubit radius. Even within this limitation, it would be forbidden to carry from the end of one roof to the beginning of another, even if it was within the four-cubit limit. On our daf , Rami bar Hama asks whether, according to this opinion, one can carry from the roof of a house to the roof of a neighboring akhsadra (portico), assuming that he remained within the four cubit limit.
The Gemara does not offer a response to Rami bar Hama’s question and continues by relating another question, this one raised by Rav Beivai bar Abaye. What if a house adjoined a hurba – a ruin? Could one carry from the roof of the house onto the roof of the hurba if he was careful to remain within the four-cubit limit?
Rav Kahana said: Is that not precisely the same dilemma raised by Rami bar Hama with regard to a portico? Rav Beivai bar Abaye said: And did I come late [me’aher] merely to quarrel, and meddle in other people’s questions? That is not the case, as the two dilemmas are not identical. A portico is not fit for residence, while a ruin is fit for residence. Therefore the halakha might differ in each case.
Rav Beivai uses an expression that is difficult to interpret – v’khi me’aher atai u’nitzai. Rashi understands it to mean “do you think that I came to make use of someone else’s question in order to argue?”
The Meiri seems to read the word me’aher slightly differently, so that it does not mean “from someone else” but “to come late.” Thus he understands the meaning to be “are you saying I came late to the Beit Midrash, missed the lesson, and that I am arguing without knowing the discussion that took place?”
Other possible versions of the Gemara led some commentaries to explain this as Rav Beivai saying about Rav Kahana, “he is arguing with me for no reason” or “he is younger than me, and yet he insists on arguing with me.”
In any case, the Gemara reaches no conclusion with regard to these questions, ending with the proverbial Teiku.