There is a maklokes Beis Shammai and Beis Hillel in the Mishneh in Sukkah Daf 28a in regards to someone who has rosh v'rubo inside of the sukkah and his shulchan inside of the house is he yotzee or not the mitzvah of sukkah. Beis Shammai says he isn't and Beis Hillel says he is. However l'maseh we pasken like Beis Shammai. Why is it that over here by this halacha we pasken like Beis Shammai over Beis Hillel?
Yehoshua, Yerushalayim, Eretz Yisrael
The Gemara earlier (3a) rules like Beis Shamai. Rav Shmuel bar Yitzchak there said that the Halachah is that a Sukah must be large enough to contain a person's head, the majority of his body, and his table. Rebbi Abba said to Rav Shmuel bar Yitzchak that this appears to follow the opinion of Beis Shamai. (Rashi cites the Gemara (28a) that says that this is Beis Shamai's opinion.) Rav Shmuel replied that this of course is the opinion of Beis Shammai. The Gemara there cites another version which reports that Rebbi Abba said that if someone should ask you who said this Halachah, you should reply that "it is Beis Shamai and do not move from this Psak." Tosfos (3a, DH d'Amar) writes that this is one of the six places where Rav Amram Ga'on ruled according to Beis Shamai.
Kol Tuv,
Dovid Bloom