Question #1: It says in Sukah (22a) that when there is [at least] a Tefach width, we say Chavut Rami even if it is more than three [Tefachim higher]. A Korah is a Tefach. We should say also Chavut Rami even if it is higher than three!

Question #2: Even without this, it is difficult why we do not permit even more than three, since the Korah is within 20 Amos!

Answer: Here we require a Korah on top of a Mavuy. When it is more than three, it is not a Heker.

Proof: When it is distanced outside [the Mavuy], even less than three [Tefachim], we do not say [that it is valid due to] Lavud (a gap less than three Tefachim is considered to be filled in).

Explanation: This is not because it is considered like a Mavuy unto itself, for a Mavuy is permitted through a Lechi or Korah only if it is longer than its width, and house and Chatzeros open to it.

Question: In Shabbos (6a), regarding "Others say that the threshold has the status of two Reshuyos. When the door is open, it is like inside [the house, Reshus ha'Yachid]. When the door is closed, it is like outside (Reshus ha'Rabim)";

[The Gemara (9a)] asks from Rav's law, that another Lechi is needed to permit carrying (opposite the Lechi), and answers that [Others] discuss the threshold of a Mavuy [permitted through a Korah].

Why didn't it answer there that [Rav] discusses [a Mavuy] open to Karmelis, and Others discuss a threshold open to Reshus ha'Rabim?

Answer: If it opens to Reshus ha'Rabim, since [the threshold] is less than four by four [Tefachim], it is Mekom Petur, and even if the door is locked, it is like inside.

Note: It seems that "like inside" merely means that it is not like outside (Reshus ha'Rabim). It is not Reshus ha'Yachid, rather, it is Mekom Petur.

Proof - Implied question: Also according to Abaye, we should establish it to discuss a height of three [Tefachim], which is Mekom Petur, like we said above!

Answer: If so, the same would apply even if [the door] is locked.

Explanation: These are not R. Yochanan's words, for Rav Ashi explains [R. Shimon ben Gamliel] differently. (Since Abaye and Rava argue about R. Yochanan's opinion, this would not answer for Rava!)

Question: If so, what was the question against Rava? He can explain that the Lechayayim were four [Tefachim] wide, for above Rava agrees when they are four wide that [Bein ha'Lechayayim] is forbidden!

And even when they are not four wide, we find that they argue [about Lavud] - R. Shimon ben Gamliel says Lavud, and all together they are four [Tefachim], and it is forbidden to use opposite them;

According to Rabanan, who do not say Lavud [past three], he may use until the outer edge of the outermost Lechi. (The Gemara said that Rabanan permit until the inner edge. If R. Yochanan himself did not say so, Rava can explain differently!)

Answer: Since when there are only two Lechayayim, and each is Mashehu [wide], and both are close within four [Tefachim], we do not find the argument of R. Shimon ben Gamliel and Rabanan - we find the argument only when they extend [at least] four [Tefachim]...

R. Yochanan should have explicitly specified in his words "a Mavuy dense with Lechayayim less than four [Tefachim] apart for a length of four [Tefachim]."

Implied question: Rav Ashi establishes it when [in all] they extend four Amos! (He says so according to R. Yochanan, even though R. Yochanan did not specify.)

Answer: Since R. Yochanan said "a Mavuy dense [with Lechayayim]", it is as if he specified four Amos, for four Amos is the [minimal] length of a Mavuy.

Explanation #1 (Rashi): Presumably, the first Lechi is distanced a little outside [the Mavuy], for this is the way of everyone who erects a Lechi. They distance it a little to the outside, so it will be seen from the outside and from inside that it was fixed there for the sake of a Lechi.

Explanation #2: It is better to explain than it is distanced a little towards the inside, for the entire Sugya connotes that Rava wants to permit until the outer edge of the Lechi;

How can he permit, if it is distanced outside, i.e. towards Reshus ha'Rabim? How can he permit [carrying in] Reshus ha'Rabim? A Stam Mavuy, the lengths of its [long] walls are the same! (If one wall were longer, and a Lechi is considered a Mechitzah, it would be enclosed by two walls, and it would be feasible to say that it is permitted.)

Explanation #1 (Rashi here): The wall recesses in front (on the outside it is intact, and on the inside, part is missing).

Explanation #2 (Rashi above on this Amud): Nir'eh miba'Chutz is when he extended the entire Lechi outside, and its inner edge enters the thickness of the wall, and it is not seen from the inside, only from the outside.

Remark: It seems that Rashi changed [his Perush], for above we discuss a Lechi erected by a wall, and it is normally erected towards the inside, and this is brought also regarding a Mavuy dense with Lechayayim, i.e. on the inside;

However, here we discuss a wall that one side is recessed from the other. It is normal to make a building like this when there are two Mavo'os one next to the other, or a house and a Chatzer next to the Mavuy. Sometimes they extend the wall by it past the wall of the Mavuy.

Question (against Explanation #2): His Perush here is better, for according to Explanation #2, if it is considered Nir'eh miba'Chutz when the Lechi is on the inside, how do we answer below "when the walls of the small [Chatzer] enter the big [Chatzer]?"

This is still Nir'eh miba'Chutz, for Gifufei ha'Gedolah (the wall of the big to the sides of where the walls of the small enter the big) are visible, for they are the thickness of the walls of the small. [The part of the walls of the small] that enters the big is like a Lechi that Rashi explained!

Suggestion: Perhaps they enter four Amos, so they lose the law of a Lechi.

Rejection: This does not apply to a Chatzer! (Planks permit a Chatzer. Also above four Amos is considered a plank.)

Answer #1: However, if what it says below "10 Amos and two Tefachim suffice" is precise (for we require a Tefach on each side), it is fine, for we discuss when [the walls] are not a Tefach thick.

Answer #2 (Ritzva): "The walls of the small enter the big" discusses when there is a Heker which are the walls of the small, e.g. the walls of the small are sloped from east to west, like they do at the top of walls, and the walls of the big are sloped from north to south. (Since it is evident that Gifufei ha'Gedolah do not pertain to the small Chatzer, they do not permit it.)

Implied question: In Nidah (46b), we find that R. Yosi taught the Beraisa of Seder Olam, and he disagrees!

Answer: He taught the words of Chachamim that preceded him. He would not teach the words of a colleague with whom he argues.