(Beraisa): If [the Eruv] was put in a basket and hung on a tree, above 10 Tefachim, it is not an Eruv. Below 10 Tefachim, it is an Eruv, but one may not move it. Below three, it is permitted [even to move it].

Question: If it is an Eruv, it should be permitted to move it. If it is forbidden to move it, it should not be an Eruv!

Answer (R. Acha citing R. Chinena): The case is, he can tilt [the basket so one end is within 10 of the ground] and Mevatel it from being [in] Reshus ha'Yachid [and take it Bein ha'Shemashos].

Inference (R. Yosah): If a bench is in Reshus ha'Rabim 10 tall and four wide, since he can tilt it and Mevatel it from being Reshus ha'Yachid, his Eruv [that he put in it] is valid and he may move it.

Question (Mishnah): If two [walls of a Sukah] are man-made and one is a tree, or two are from trees and one is man-made, it is Kosher, but one may not go up in it on Yom Tov. Here you say that his Eruv is valid and he may move it?!

Answer #1 (R. Yirmeyah): Here [we forbid regarding Sukah when the Sechach is] above (on the tree itself). Here (we permit moving an Eruv when the basket is) on the side (hanging from a peg inserted into the tree - PNEI MEIR, HA'GAON RAV C. KANIEVSKY, SHLITA).

We learn this (Sukah) from that (Eruv), and that (Eruv) from this (Sukah);

We learn this (Sukah) from that, that if two pegs came out [from a tree], and he put Sechach on them, it is Kosher, and one may not go up in it on Yom Tov.

And we learn that (Eruv) from this, that if he put it on the tree itself, his Eruv is valid and he may not move it.

Answer #2 (R. Yosah): Both here and there (Eruv and Sukah), it is on the side.

Question: How is this? (Why may one move the Eruv, but not ascend the Sukah on Yom Tov?)

Answer: It is like R. Yakov bar Acha said in the name of R. Ze'ira. [R. Yosah's teaching of the bench] is like R. Shimon ben Elazar;

(Beraisa - R. Shimon ben Elazar): One may use sides of an animal on Shabbos.

The sides of an animal and the sides of a tree are the same. (The Mishnah is like Chachamim, who forbid the sides of a tree.)

Question: (Our Mishnah is Machshir an Eruv in a pit, even 100 Amos deep. It disqualifies an Eruv in a tree above 10.) Do you not view depth like height?! (Also here he cannot bring the Eruv in the pit to where he is, above! We explained this like YERUSHALMI KI'PESHUTO, HA'GAON RAV C. KANIEVSKY, SHLITA.)

Answer (Aba bar Rav Huna): The case is, he said "my Shevisah is below'' (where the Eruv is).