Sukkah, Daf Yod Het, Part 1
Introduction
We continue to discuss how large a gap of air invalidates a sukkah.
אמר אביי: אויר שלשה בסוכה גדולה ומיעטו בין בקנים בין בשפודין – הוי מעוט. בסוכה קטנה, בקנים – הוי מיעוט, בשפודים – לא הוי מיעוט.
Abaye ruled: An air space of three handbreadths in a large sukkah which is diminished with either sticks or spits is a [valid] diminution; in a small Sukkah, with sticks it is a [valid] diminution, with spits an invalid one.
Abaye holds that if one wants to diminish a gap in a sukkah there is a difference between a large and a small sukkah. A three handbreadth gap in a large sukkah can be diminished even with invalid skhakh because once he diminishes the gap, there will no longer be a three handbreadth gap of air.
However, if the sukkah is small he can diminish it with sticks, which are valid as skhakh. Since a less than three handbreadth gap is negligible (lavud), the sukkah is valid. However, if he does so with spits, which are not valid skhakh, the sukkah is not valid, even though there isn’t a minimum measure of air space or a minimum measure of invalid skhakh. Since of the seven handbreadths of the sukkah (the minimum measure of a sukkah) more than three aren’t valid (either air or spits) there isn’t sufficient skhakh to validate the sukkah.
והני מילי מן הצד. אבל באמצע – פליגי בה רב אחא ורבינא. חד אמר: יש לבוד באמצע, וחד אמר: אין לבוד באמצע.
This applies only to the side, but as regards the middle, R. Aha and Ravina differ.
One says: the rule of lavud applies in the middle, while the other says, the rule of lavud does not apply in the middle.
The Talmud limits Abaye’s statement to a case of a gap on the side of the skhakh. If there is an air gap of less than three handbreadths on the side of the sukkah, the sukkah remains valid for we can invoke the rule of "lavud." However, when it comes to such a gap in the middle of the sukkah, there is a dispute between two amoraim. One holds that the rule applies in the middle as well. The other holds that it does not.
מאי טעמא דמאן דאמר יש לבוד באמצע – דתניא: קורה היוצאה מכותל זה ואינה נוגעת בכותל אחר, וכן שתי קורות אחת יוצאה מכותל זה ואחת יוצאה מכותל אחר, ואינן נוגעות זו בזו, פחות משלשה – אינו צריך להביא קורה אחרת, שלשה – צריך להביא קורה אחרת.
What is the reason of him who says that the rule of lavud applies in the middle? Because it has been taught: If a beam protrudes from one wall but does not touch the opposite wall, and similarly in the case of two beams, one protruding from one wall and one from the other and not touching each other, if [the space between them is] less than three [handbreadths] it is unnecessary to provide another beam; if it is three [handbreadths] it is necessary to provide another beam.
The amora (we don t know which one) who holds that the rule of lavud applies in the middle derives this from a baraita. The baraita is not discussing a sukkah but rather the beams laid across an entrance to an alleyway on Shabbat. These beams are part of the eruv system and allow one to carry from one courtyard to another on Shabbat. One thing that needs to be done is to lay a beam across the alleyway entrance. The baraita teaches that as long as there is not a gap of three handbreadths between the beam and the wall or between one beam and the other, the system works. This is even true if the gap is in the middle, one beam coming from one side and the other beam coming from the other side. Thus the rule of "lavud" can be applied even in the middle.
ואידך: שאני קורות דרבנן.
And [what does] the other [answer to this]? Beams are different [from a sukkah] since [they are only] a rabbinical measure.
The amora who holds that the rule of lavud is not invoked in the middle rejects the proof from the baraita because all of the rules of eruvin, including the beam that allows one to carry from one alleyway to another, are only "derabanan" of rabbinic origin.