(Mishnah): If Shimon brought his pots into Reuven's yard without permission, and Reuven's animals broke them, he is exempt;

If Reuven's animals were damaged by the pots, Shimon is liable.

If Shimon had permission to bring them in, Reuven is liable.

(Gemara): If Shimon brought his pots into Reuven's yard without permission, and an ox came from elsewhere and broke them, [the owner] is exempt. If it was damaged through them, [Shimon] is exempt.

(Inference): This teaches that Regel is exempt in a Chatzer that does not belong to either of them (not the damager and not the victim. We changed explained this like R. MEIR SIMCHAH and others. The text 'ha'Keren' is very difficult, for above (6a, Sof 1:2) it says that wherever there is not Reshus for this one or for this one, Keren is liable! Also, how would the Gemara infer that this discusses Keren? Normally, Keren is taught about damage to animals! (PF) Also, Halachah 3 discusses Shen, and Halachah 4 discusses Keren. Would the Tana teach Keren, Shen, and Keren again, and omit Regel?!)

(Mishnah): If Shimon brought his Peros into Reuven's yard without permission, and Reuven's animals ate them, he is exempt;

If Reuven's animals were damaged by the pots or fruit, Shimon is liable.

If Shimon had permission to bring them in, Reuven is liable.

(Gemara): If Shimon brought his Peros into Reuven's yard without permission, and an ox came from elsewhere and ate them, [the owner] is exempt. If it was damaged through them, [Shimon] is exempt.

(Inference): This teaches that Shen is exempt in a Chatzer that does not belong to either of them.