Gemara

28a - Mishnah: All seven days one makes his Sukah Keva and his house Arai.

Beraisa: "Teshvu" - k'Ein Taduru (dwell in the Sukah the way you live in your house). If one has nice Kelim and linens, he brings them into the Sukah. One eats, drinks, roams and learns in the Sukah.

Question: Rava taught that one recites written Torah and Mishnayos in the Sukah, but one may learn (the reasons for Mishnayos and resolving difficulties) outside the Sukah (if one's mind is clearer outside)!

Answer: We distinguish between reciting teachings that one already knows and investigation (of the reasons and resolutions).

After Rava and Rami bar Chama heard Rav Chisda teach, they would recite the Halachos. Later, they would ponder the reasons for them.

Rava: Kelim for drinking are in the Sukah. Kelim for eating, a jug for drawing water and a pail are out of the Sukah.

Some say that a lamp should be in the Sukah, and some say that it should be outside.

They do not argue. It should be inside a big Sukah, but not inside a small one.

48a - Question: If one has no place to eat (other than the Sukah, on Yom Tov after Sukos), what should he do (to show that he does not intend to add to the Mitzvah)?

Answer #1 (Chiya bar Rav): He makes an opening of four Tefachim (in the Sechach).

Answer #2 (R. Yehoshua ben Levi): He lights a Ner inside.

They do not argue. Chiya's answer is for people in Eretz Yisrael, and R. Yehoshua's answer is for people in Bavel (this will be explained).

Question: This helps for a small Sukah. What can he do for a big Sukah?

Answer #3: He brings in Kelim for food;

Rava: Kelim for food are out of the Sukah.

Rishonim

The Rif and Rosh (2:18,19) bring the above teachings (the Rif omits the jug and pail).

Ran (DH Gemara): Rashi says that it is an exertion to investigate learning. Since it is painful, he is exempt from Sukah. The air helps settle his mind. Others say that investigation is Keva, so it must be in the Sukah. One should be stringent for both opinions and learn everything in the Sukah. However, if he is distracted this is painful, so he is exempt.

Ran (DH Amar): Some explain Kelim for eating and drinking like learning, i.e. drinking Kelim must be in the Sukah, and eating Kelim may be outside. The Rif explains that drinking Kelim may be in the Sukah, and eating Kelim must be outside.

Rif (Sof Sukah): A lamp disqualifies a small Sukah. Bringing in Kelim for food disqualifies the Sukah.

Rebuttal (Ba'al ha'Ma'or): Granted, a lamp could disqualify a small Sukah by diminishing the Shi'ur. But bringing in Kelim for food does not disqualify a big Sukah. It is a mere Heker that he does not intend for the Mitzvah.

Defense #1 (Hasagos ha'Ra'avad): Chiya bar Rav required opening four Tefachim to disqualify the Sukah. He did not say that a small amount suffices for a Heker. Likewise, bringing in Kelim disqualifies!

Note: The Gemara did not specify why people in Bavel cannot make an opening in the Sechach. Rashi says that they cannot do so at the end of the seventh day, for they must eat in a valid Sukah on Shemini Atzeres. This implies that the solution for Bavel, to bring in a lamp or food Kelim, does not disqualify! The Ra'avad must explain like the Rosh (4:7), that Benei Bavel cannot make an opening at the end of Shemini Atzeres to disqualify the Sukah for the ninth day, for this is forbidden on Yom Tov.

Defense #2 (Milchamos Hash-m): Indeed, the Rif does not literally mean that the Sukah is Pasul. Rather, it makes it look unlike Dirah.

Rambam (Hilchos Sukah 6:5): The Mitzvah of Yeshivas Sukah is to eat, drink and live in the Sukah all seven days, day and night, the way he lives in his house the rest of the year. All seven days he makes his Sukah Keva and his house Arai. Nice Kelim and linens go in the Sukah. Drinking Kelim such as cups and bottles are inside. Kelim for eating such as pots and bowls are outside. A lamp should be in the Sukah. If the Sukah is small it should be outside.

R. Mano'ach: All the more so spits and pans must be outside. They are not normally in a Beis Dirah, rather, in a pantry. Drinking Kelim even of wood or earthenware are considered nice Kelim that go in the Sukah. A lamp should be outside a minimal Sukah, even at the time of eating, lest it make the Sukah too hot and one will leave.

Lechem Mishneh: The Magid Mishnah says that a lamp should be outside when it is not lit. This is like Kelim for eating after eating. When it is needed, it is permitted.

Rambam (9): All seven days he recites (Divrei Torah) in the Sukah. When he ponders and investigates his learning he does so outside, so his mind will be settled. One may choose to pray in the Sukah or outside.

R. Mano'ach: One blesses on anything that requires a Sukah, including learning. Rav Hai Gaon says that one who visits a friend's Sukah must bless, even if he does not eat or drink in it.

Rosh (ibid.): One who investigates his learning needs a settled mind, so it is painful for him to be in the Sukah. The Gemara discusses Kelim after eating and drinking form them. Dirty Kelim for eating are repulsive, so they must be outside. Used drinking Kelim are not repulsive, so they may be inside. However, a lamp should not be in a small Sukah even when it is lit, lest it get close to the walls and set them afire.

Hagahos Ashri: BaHaG and Sefer ha Mitzvos say that 'Kelim for eating' refers to kneading bowls, but regular bowls may be left in the Sukah after eating

Poskim

Shulchan Aruch (OC 639:1): The Mitzvah of Yeshivas Sukah is to eat and drink (Rema - and sleep and roam) in the Sukah all seven days, day and night, the way he lives in his house the rest of the year. All seven days he makes his Sukah Keva and his house Arai.

Darchei Moshe (1): If one wants to play with dice or talk with friends he should do so in the Sukah. He should treat the Sukah like his house.

Kaf ha'Chayim (5,6): One should speak only Divrei Kedushah in the Sukah because it has great Kedushah. Kedushah takes effect even on the wood. Batel words are forbidden even outside the Sukah. Severe curses were said regarding people who play dice even during the year. The Ushpizin are present, so one should be in the Sukah in awe, fear, shame and humility. One should not be drawn after eating and drinking, lest he come to indecency. One should not bring a Nochri inside, for Sukah is Tzelah d'Mehemnusa. Nochrim lack this, and they cause the Kedushah to depart and the Ushpizin to curse.

Shulchan Aruch (ibid.): Nice Kelim and linens go in the Sukah. Drinking Kelim such as cups and bottles are inside. (After eating,) Kelim for eating such as pots and bowls are outside.

Bach (DH Kosav ha'Rif): Some say that food Kelim in the Sukah disqualify it. This is wrong. The Ramban and Ran explain that the Rif never meant that they disqualify it.

Kaf ha'Chayim: The Ra'avad says that the Rif really disqualifies it, and he agrees. Some say that it is Pasul mid'Rabanan when the Kelim are inside.

Magen Avraham (3): The Beis Yosef forbids washing pots and bowls. This implies that one may wash cups.

Mishnah Berurah (3): We are lenient about drinking Kelim because even after use they are not repulsive. Also, there is no limit to how often one drinks during the day.

Mishnah Berurah (4): The Shulchan Aruch permits bringing in pots to pour into the bowls. People are careful not to bring in pots in at all. Perhaps they are concerned for those who always forbid pots; perhaps the Shulchan Aruch itself holds like this. Certainly one who normally does not bring pots to the table should not bring pots to the Sukah. If one has no other Keli he may bring the pot in. People leave bowls in after eating; this is improper.

Shulchan Aruch (ibid.): A lamp should be in the Sukah. If the Sukah is small it should be outside.

Beis Yosef (DH v'Chosvu and Kosav b'Hagahos): We following the majority of Meforshim, who forbid a lit lamp in a Sukah. Also, they bring a proof (48a). Or Zaru'a says that the same applies even if the lamp is new or of gold. The Roke'ach says that the custom is to bring only metal lamps or candles.

Darchei Moshe (2): This is because earthenware lamps are repulsive, unless they are plated.

Taz (3): Rashi says that a lamp should not be in a minimal size Sukah. This implies that the problem is that it diminishes from the Shi'ur. It is not clear why this is different than Sechach on pillars around a bed (631:13). There it is Kosher even if the Sechach is less than 10 above the bed, because if the bed would be removed there would be a Shi'ur. Likewise, if the lamp would be removed there would be a Shi'ur! It seems that Rashi discusses a lamp hanging from the Sechach, but otherwise it is permitted. According to Tosfos it should not be inside whenever it is a fire hazard.

Kaf ha'Chayim (20): After the lamp goes out one should take it outside.

Rema: One should not do anything disgraceful in the Sukah, lest Mitzvos be disgraceful to him.

Kaf ha'Chayim (22): Most opinions permit marital relations, for this is not disgraceful. However, one should ensure that there are curtains to block moonlight.

Shulchan Aruch (4): All seven days he recites (and learns) Torah in the Sukah. Investigation of what he recites (and learns) is (permitted) outside, so his mind will be settled.

Mishnah Berurah (29): If it is difficult to bring his Seforim to the Sukah, he is exempt. This does not apply if he has a place to put them for all of Sukos.

Shulchan Aruch (ibid.): One may choose to pray in the Sukah or outside.

Magen Avraham (14): If there is a Beis ha'Keneses in the city he should pray there. If not, he prays in the Sukah if his mind is settled there.

Taz (13): The entire year one prays in the Beis ha'Keneses, not at home, therefore he need not pray in the Sukah.