From: Rabbi Akiva Eiger
To: Rabbi Shmuel
Rabbi Akiva Eiger rejects his son-in-law's proof from Gittin 43a that a male treifah cannot sire offspring, noting the Beraisa's language is problematic regardless, while citing independent proofs from Chullin and Temurah. He resolves the kofer question by showing Reish Lakish's principle is based on textual exegesis rather than conceptual linkage, and resolves the Gittin 74 difficulty by invoking the Rosh's principle that a conditional divorce creates a quarrel negating the presumption of einah me'izah.
Source: Shu"t Rabbi Akiva Eiger §204