On Daf 7b, Abaye lists an entire string of Tana'im who hold "Diras Keva Ba'inan," including Acherim, Rebbi Yoshi'a and Rebbi Shimon.
(a) Acherim disqualify a round Sukah. Why is a round Sukah considered to be "Arai"? What difference does it make if it has corners or not, as far as Keva or Arai is concerned?
(b) I am bothered by the same question according to Rebbi Yoshi'a. Rebbi Yoshi'a requires walls that are Tzelzah Merubah - what does that have to do with Arai or Keva?
(c) According to Rebbi Shimon, who says that a Sukah has to have four walls in order to be Keva and protect from the rain, will Lavud help on those walls? After all, the rain can still enter through the Lavud gap.
Thank you,
Avi Feldman
(a) The Ran (on the Rif 3b) says that a round Sukah is considered Arai because it is not usual to build a Diras Keva in this way. This would seem to imply that the reason Acheirim disqualify a round Sukah is because they hold that a Sukah must resemble a permanent structure. Even if a person built a round Sukah in a permanent way this is not acceptable according to Acheirim, because a Sukah must be built the way a permanent structure is usually built.
(b) We could say the same answer for Rebbi Yoshiya, since a normal Diras Keva gives more shade than sun. Perhaps here we could say an even simpler explanation, since any place where there is more sun than shade is not conducive to permanent dwelling.
(c) Rebbi Shimon learns from the Pasuk that a Sukah needs to be made in a form that is capable of protecting one from the elements. However, this does not mean that the Sukah must actually do this, only that it must have the number of walls that are capable of doing so.
Dov Freedman