1)

(a)The Din in all the combinations of two Sukos, one above the other dealt with in the previous Beraisa, is obvious - except for the third case (where the bottom Sukah is Kasher and the top one, Pasul).

(b)We might have thought that the bottom one is Pasul too - because we would have expected Chazal to decree when the top Sukah is lower than twenty Amos because of where it is higher (when it would invalidate the lower Sukah because of Sechach Pasul).

2)

(a)According to Rav Huna, the distance between one Sukah and the other for it to be considered a Sukah underneath a Sukah (and not one combined Sukah) is one Tefach - which he learns from the Mishnah in Ohalos, where the smallest Shi'ur Ohel is one Tefach (as we shall now see).

(b)When the Mishnah in Ohalos says 'Tefach al Tefach b'Rum Tefach ...

1. ... Meivi es ha'Tum'ah' - it means that, if an object is lying underneath one end of an Ohel (e.g. a projecting piece of wood) which measures at least a Tefach by a Tefach, and a piece of corpse under the other end, the Ohel transmits Tum'ah from the corpse to the object, provided it is one Tefach from the ground.

2. ... Chotzetz Bifnei ha'Tum'ah' - it means that, if the object is on top of the Ohel, directly above the corpse, then the Din will work in the reverse, to protect an object that is on top of the Ohel from becoming Tamei Mes, even if it is directly above the Mes, provided it is one Tefach from the ground.

(c)Rav Chisda and Rabah bar Rav Huna give the distance between the two Sukos as four Tefachim - because here it is a question of a Makom Chashuv, and the minimum area that falls under the category of Makom Chashuv is four Tefachim (like we find on Shabbos).

(d)Shmuel is far more radical than the previous two opinions. He requires at least ten Tefachim between the two Sukos ...

(e)... because, just as a Kasher Sukah must be ten Tefachim tall, so too, can it only render another Sukah Pasul if it is ten Tefachim tall.

3)

(a)According to Rebbi Yehudah in our Mishnah, if there is nobody living in the top Sukah, the bottom one is Kasher. This cannot be meant literally however - because why should the fact that there is nobody residing in the top Sukah remove the Pesul of a Sukah underneath a Sukah?

(b)What he therefore means is that it is not fit to live in - which we initially take to mean that there is less than ten Tefachim between the two Sukos, which is why Rebbi Yehudah validates the Sukah, and the Rabanan invalidate it - a Kashya on Shmuel, according to whom only a Sukah that is ten Tefachim tall can invalidate a second Sukah because of Sukah she'Tachas ha'Sukah.

(c)When Rav Dimi arrived from Eretz Yisrael, citing the Bnei Eretz Yisrael, he established the Mishnah - where the lower Sukah is not strong enough to hold the bedding of the people sleeping in the top one.

(d)And the reason that ...

1. ... Rebbi Yehudah renders the Sukah Kasher is - because he considers the top Sukah unfit to be used as a residence, and therefore unable to invalidate the bottom Sukah.

2. ... the Rabanan invalidate the bottom Sukah - because they consider the top Sukah a residence which will therefore invalidate the bottom one.

4)

(a)Our Mishnah invalidate a Sukah which has a sheet spread across it, either on top, to protect the Sukah from the sun, or underneath, to protect it from the droppings of Sechach - because a sheet is subject to Tum'ah, and is therefore not eligible to be used as Sechach.

(b)Sleeping underneath a four-poster bed over which a sheet has been draped, is not forbidden for the same reason - because the sheet was not placed there to be used as Sechach.

(c)One may nevertheless not sleep underneath it - because one is sleeping under an Ohel, and not under Sechach.

(d)One may however, spread a sheet over 'Naklitei ha'Mitah' - a two-poster bed, where the angle of the draped sheet is too acute to be considered an Ohel.

5)

(a)A canvass with pictures spread across the ceiling to adorn the Sukah, does not invalidate it - because whatever is to adorn becomes Batel to whatever it is adorning.

(b)Rav Chisda needs to tell us this, despite our Mishnah, which forbids a sheet that is spread across the Sukah to protect it from the sun or from the droppings, but omits any mention of one that decorates it - because we would have thought that the Tana only deals with more usual cases (but does not necessarily preclude what is more unusual, such as decorative hangings).

6)

(a)The Beraisa forbids taking down and using the ornaments that are hanging in the Sukah until after Shemini Atzeres, listing various types of colored hangings, nuts, and fruits etc. as examples of this - either because they are Muktzeh, or because of 'Bizuy Mitzvah' (treating an object of Mitzvah with disrespect).

(b)One will be permitted to take then down and use them - provided one stipulated before Yom-Tov entered, that one retained full ownership over them throughout the period of Bein-ha'Shemashos (dusk).

(c)There is no proof from this Beraisa that ornamental hangings that are spread across the ceiling do not invalidate the Sukah - because the Beraisa may well be speaking about ornamental hangings that are hanging on the wall, and not from the ceiling.

7)

(a)Ornaments ...

1. ... that are suspended from the Sechach are neither Machshir the Sukah if it is more than twenty Amos high, nor do they render it Pasul if it is exactly ten Tefachim high) - because they are not considered Sechach.

2. ... that are attached to the wall of a Sukah that is exactly seven by seven Tefachim wide do however, render the Sukah Pasul - because they render the Sukah uninhabitable.

(b)Rav Ashi instructed Menimin to remove the wet shirt from the roof of the Sukah, where he had hung it up to dry - because it looked as if he was using the shirt as Sechach, to cover the Sukah.

(c)Menimin was Rav Ashi's servant.

(d)It may well have been obvious that the shirt was hung up to dry (and not to cover the Sukah) - as long as the shirt was wet. But when Rav Ashi instructed Menimin to remove it, he meant after it had dried.

8)

(a)According to Rav Nachman, ornaments that are dangling below four Tefachim, do not invalidate the Sukah. Rav Chisda and Rabah bar Rav Huna hold - that they do.

(b)When Rav Nachman arranged for Rav Chisda and Rabah bar Rav Huna to sleep in the Resh Galusa's Sukah, where ornaments were dangling below four Tefachim did not - the latter did not react ...

(c)...because, even though this did not conform with their opinion - they remained unconcerned, due to the fact that they were Sheluchei Mitzvah (visiting their Rebbe, the Resh Galusa), and were exempt from the Mitzvah of Sukah.

(d)In his capacity as the head of Beis-Din - Rav Nachman had the authority to organize the Resh Galusa's household (He also happened to be the R.G.'s son-in-law).

9)

(a)Rav Yehudah Amar Shmuel permits sleeping in a Kilas Chasanim, provided the posts over which the sheet is draped are less than ten Tefachim tall, and the Beraisa, which forbids sleeping in a four-poster bed, is referring to when the posts are taller than ten Tefachim.

(b)the Mishnah in 'ha'Yashein', which renders not Yotzei someone who sleeps underneath a bed on Sukos - also speaks about a bed that is taller than ten Tefachim.

(c)We can infer from the Beraisa, which, after prohibiting sleeping under a sheet that is draped over a four-poster bed, permits sleeping under a sheet that is draped over a two-poster bed, provided it is less than ten Tefachim tall - that sleeping under the sheet of the four-poster bed is forbidden even if it is less than ten Tefachim tall (not like we just said in the previous answer).

(d)Nevertheless, Rav Yehudah permits a Kilas Chasanim that is less than ten Tefachim tall - because a Kilas Chasanim (unlike a four-poster bed, which is permanently fixed) is only a temporary fixture, and the Chachamim were therefore more lenient.

10)

(a)We just forbade sleeping under a four-poster bed, even if it is less than ten Tefachim high. Nevertheless, Shmuel learnt earlier that a Sukah that is underneath a Sukah is Kasher, provided less than ten Tefachim separate them (despite the fact that the top Sukah is also fixed) - because (unlike a four-poster bed, which invalidates the Sukah because it is an Ohel) the latter would invalidate the Sukah because it is a Sukah, and a Sukah can only invalidate if it is a Kasher Sukah (as we learned earlier 'ke'Hechsheirah Kach Pesulah').

11)

(a)Based on the previous Halachah, Rav Tachlifi bar Avimi Amar Shmuel permits someone who is sleeping naked in a Kilas Chasanim to stick his head outside the sheet that is less than ten Tefachim from his body, and recite the Shema - because, seeing as the sheet is not considered an Ohel, it is as if it was placed directly on top of him, in which case reciting the Shema with his head outside the sheet is permitted (see also Tosfos DH 'Motzi).

(b)In the same case, but where he was sleeping in a four-poster bed, Shmuel would concede that this is forbidden - since there the sheet has a Din of Ohel, and we would therefore consider his head to be where the rest of his body is.

(c)As for the Beraisa which forbids reciting the Shema even in a Kilas Chasanim - Shmuel will establish it where the sheet is higher than ten Tefachim.

(d)We prove this answer from the Seifa of the Beraisa, which forbids a naked person to stick his out of the window and recite the Shema (even if the ceiling is less than ten Tefachim high - because, like in the case of a four-poster bed, the ceiling, which is permanently fixed, has the Din of Ohel).