On Bovo Kamma 41a, the Gemoro suggests an approach based on Rebbi Abohu, but then rejects it ("Hani Mili..."). The Gemoro then asks a Kashe ("Maskif Lo Mar Zutra..."), and refutes the Kashe ("Omri...").
On 41b (line 5), the Gemoro then proceeds to explain this approach further ("Hashta..."). Did I miss something - I thought we said Rebbi Abohu was not applicable here?!
Kol Tuv
Meir Eliezer Bergman, Manchester UK
Many Rishonim deal with this question. Perhaps the biggest Chidush is the Tosfos Ha'Rosh, who says that the Beraisa was not actually making a Derashah, but saying where we would learn from if not for Rebbi Avahu's Derashah. The Ritva in Kidushin quotes Rashi (though this is not indicated by our text of Rashi) as answering simply that the Beraisa argues on Rebbi Avahu, and the Gemara is now pursuing Rebbi Avahu's undertanding. [For these and other answers, see the Dvar Yaakov here.]
All the best,
Yaakov Montrose