1. There is a dispute about whether a barrel of wine found in a river is permitted (and not deemed Yayin Nesech).
2. The Gemara suggests that this dispute is based on the argument of Rov and Karov (see Daf 23, #5).
3. The Gemara rejects this interpretation of their argument.
4. A pot of food being cooked by many people is neither hot nor cold.
5. A permanent silo cannot be established within 50 Amos of a city.
A BIT MORE
1. Rav: If it is found in a place that is mostly Jewish, it is permitted. Shmuel: Even if it is found in a place that is mostly Jewish it is forbidden; we suspect that it floated there from a place that is mostly non-Jewish.
2. Rav: Karov overrules Rov. Shmuel: Rov overrides Karov.
3. The Gemara concludes that this argument (#1) is specifically in the case being discussed by Rav and Shmuel regarding a Nochri city that was upstream from the Jewish cities along the Peras River. Rav understood that the barrel would almost certainly stay in the area of the Nochri city, while Shmuel said it was more likely to get to the Jewish city.
4. In other words, when many people have a share in doing one job, it gets started but does not get completely done, as each person depends on another one of the partners to complete the job.
5. This is because, during winnowing, the wind carries the chaff to the city and damages it.