(Mishnah): If there is an inner Chatzer and an outer Chatzer - if only the inner Chatzer was Me'arev, it is permitted [to transfer between its houses and the inner Chatzer], and the outer Chatzer is forbidden;

If only the outer Chatzer was Me'arev, both are forbidden.

If each was Me'arev by itself, each is permitted by itself [but one may not transfer from one Chatzer to the other];

R. Akiva forbids the outer Chatzer due to Drisas ha'Regel of the inner Chatzer;

Chachamim say, Drisas ha'Regel does not forbid.

(Gemara - R. Yosah): [The Reisha] is like R. Akiva, for R. Akiva says that Drisas ha'Regel forbids.

(R. La): [It is even like Chachamim. They agree that] Drisas ha'Regel [of a Chatzer that is] forbidden forbids.

(Mishnah): If an outer person forgot to be Me'arev, the inner Chatzer is permitted, and the outer Chatzer is forbidden;

If an inner person forgot, both Chatzeros are forbidden;

If both Eruvin were put in one place, and someone forgot to be Me'arev, whether he is in the inner or outer Chatzer, both Chatzeros are forbidden;

If each Chatzer had only one resident, they need not be Me'arev.

(Gemara): [In the Seifa,] if an outer person forgot to be Me'arev, the outer Chatzer is forbidden, for it was not Me'arev. The inner Chatzer is forbidden, for they put their Eruv in a place that is forbidden (this will be explained);

If an inner person forgot to be Me'arev, the inner Chatzer is forbidden, for it was not Me'arev. The outer Chatzer is forbidden, for they put their Eruv in a place that is forbidden. (If they put it in the inner Chatzer, it was not Me'arev. If they put it in the outer Chatzer, it is forbidden due to Drisas ha'Regel.)

Question: If an outer person forgot to be Me'arev - granted, the outer is forbidden, for it was not Me'arev. Why is the inner forbidden - because they put their Eruv in a place that is forbidden? [If they put it in the inner Chatzer,] they did not put their Eruv in a place that is forbidden!

Answer #1: Drisas ha'Regel forbids [them].

Rejection: There is no Drisas ha'Regel that forbids here! (The outer does not pass through the inner. We explained this like MEICHAL HA'MAYIM.)

Answer #2 (R. Yosa): Since [both] put their Eruv in one place, it all becomes one Reshus.

(R. Chunah citing Rav): The law of Chatzer does not apply to a Nochri. The law of Dakah does not apply to a Nochri. (These will be explained.)

The law of Chatzer does not apply to a Nochri - if he dwelled in the inner [Chatzer], you take him out (consider him to be together with Yisraelim in the outer Chatzer) to forbid [them];

The law of Dakah does not apply to a Nochri - if he dwelled in the upper story, you lower him (consider him to be together with Yisraelim below, even if he put a wall 10 Tefachim tall in front of his opening to remove his Drisas ha'Regel from them) to forbid.

(R. La citing R. Elazar): The law of Chatzer applies to a Nochri - if a Yisrael and Nochri dwelled in the inner, [and a second Yisrael in the outer, the Nochri] does not forbid until both Yisraelim [are in the same Chatzer as he is].

(R. Ba citing Rav Yehudah): If one has a Dakah in front of his house 10 tall, a Yisrael does not forbid. A Nochri forbids. (We explained this like R. MEIR SIMCHAH.)

Contradiction: R. Ba contradicts himself! There, R. Ba cited Rav Yehudah citing Shmuel to say that a wall [10 tall] surrounded by ladders on each side, they make two Eruvin, but not one (the ladders are not considered like an opening. Why does a Dakah help for a Yisrael?)

Answer (R. Yosi bei R. Bun): There, are the ladders judged like openings?! (The case is, they are not opposite each other. It is not easy to ascend one and walk on the wall, until he reaches the other.) However, here, it is normal for the top people to descend, but it is not normal for the lower people to ascend. (Therefore, a Dakah helps for a Yisrael. We explained this like PNEI MOSHE.)