One permits it because [in the open area] there are no tenants; and the other forbids this, because sometimes [it may happen] that there would be tenants in it and they would still be moving objects [from the one into the other]. If a karpaf was larger than two beth se'ah and was not enclosed for dwelling purposes, and it is desired to reduce the size thereof, then if it was effected by means of trees the reduction is invalid. If a column, ten handbreadths in height and four handbreadths in width, was built up it is a valid reduction. If [the column was] less than three [handbreadths wide] it constitutes no valid reduction. [If it is] between three and four [handbreadths wide] it is, said Rabbah, a valid reduction; but Raba maintained: It is no valid reduction. Rabbah said that it was a valid reduction, since [such a size] is excluded from the law of labud. Raba maintained that it was not a valid reduction, because so long as it does not cover a space of four [handbreadths in width] it is of no importance. If at a distance of four handbreadths from the wall a partition was put up the act is legally effective, [but if the distance was] less than three [handbreadths the partition] is ineffective. [If the distance was] between three, and four [handbreadths, the partition is], said Rabbah, effective, but Raba maintained: It is ineffective. Rabbah said that it was effective since [such a distance] is excluded from the law of labud. Raba maintained that it was ineffective because so long as it does not extend over four handbreadths it is of no importance. R. Shimi taught [that the discussion related] to [the more] lenient [procedure]. If the fence was smeared with plaster and [the layer is so thick that it] can stand by itself it constitutes a reduction; where it cannot stand by itself it [nevertheless], said Rabbah, constitutes a reduction, but Raba maintained: It does not constitute a reduction. Rabbah said that it constituted a reduction because now at any rate it stands. Raba maintained that it constituted no reduction because in view of the fact that it cannot, stand by itself it possesses no validity whatsoever. If at a distance of four handbreadths from a mound a partition was put up it is effective. [If, however, it was put up at a distance of] less than three [handbreadths] [from it] or [was actually put up] on the edge of the mound [there is a difference of opinion between] R. Hisda and R. Hamnuna. One holds that this is effective and the other maintains that it is ineffective. You may conclude that it was R. Hisda who held that [the partition] is effective; for it was stated: If one partition was put up upon another, it is, R. Hisda ruled, effective as regards [the laws of] the Sabbath but no possession of the property of a proselyte [may thereby] be acquired; and R. Shesheth ruled it is ineffective even in [respect of the laws of] the Sabbath. This is conclusive. R. Hisda stated: R. Shesheth, however, agrees with me that if a man put up a fence on the mound it is effective. What is the reason? — Because the man dwells in the space between the upper fences. Rabbah b. Bar Hana enquired: What if the lower fences were sunk in the ground and the upper ones remained standing? In what [respect does this matter]? If [it be suggested] in respect [of acquiring possession] of the estate of a proselyte, [is not the principle here involved, it may be retorted,] exactly the same [as that underlying a ruling] of Jeremiah Bira'ah who ruled in the name of Rab Judah: If a man threw vegetable seeds into a crevice of a proselyte's land and then another Israelite came and hoed a little, the latter does, and the former does not acquire possession, because at the time the former threw [the vegetable seed] he did not improve [the ground] and any eventual improvement came automatically? If, on the other hand, [it be suggested that the question arises] in respect of [the laws of] the Sabbath, [such a partition, surely, it could be retorted, is] one that was put up on the Sabbath concerning which it was taught: Any partition that is put up on the Sabbath, whether unwittingly or presumptuously, is regarded as a valid partition? — Has it not, however, been stated in connection with this ruling that R. Nahman ruled: This was taught only in respect of throwing, but the moving [of objects within it] is forbidden? — When R. Nahman's statement was made it was in respect of one who acted presumptiously. A certain woman once put up a fence on the top of another fence in the estate of a proselyte, when a man came and hoed [the ground] a little. [The latter then] appeared before R. Nahman who confirmed it in his possession. The woman thereupon came to him and cried. ‘What can I do for you’, he said to her, ‘Seeing that you did not take possession in the proper way?’ If a karpaf [was of the size of] three beth se'ah and one beth se'ah was provided with a roof, its covered space, ruled Rabbah, causes it still to be deemed bigger [than two beth se'ah], but R. Zera ruled: Its covered space does not cause it to be deemed bigger. Must it be assumed that Rabbah and R. Zera differ on the same principle as that on which Rab and Samuel differed? For was it not stated: If an exedra was situated in a valley, it is, Rab ruled, permitted to move objects within all its interior; but Samuel ruled: Objects may be moved within four cubits only. Rab ruled that it was permitted to move objects in all its interior, because we apply [the principle:] The edge of the ceiling descends and closes up. But Samuel ruled that objects may be moved within four cubits only, because we do not apply [the principle:] The edge of the ceiling descends and closes up? 56ᵃᵇᶜᵈᵉᶠᵍʰⁱʲᵏˡᵐⁿᵒᵖᵠʳˢᵗᵘᵛʷˣʸᶻᵃᵃᵃᵇᵃᶜᵃᵈᵃᵉᵃᶠᵃᵍᵃʰᵃⁱᵃʲᵃᵏᵃˡᵃᵐᵃⁿᵃᵒᵃᵖᵃᵠᵃʳᵃˢᵃᵗᵃᵘᵃᵛᵃʷᵃˣᵃʸᵃᶻᵇᵃᵇᵇᵇᶜᵇᵈ