It is obvious that if Reuven says 'Yachlok P'loni bi'Nechasai' the recipient receives half his property. Besides a healthy person distributing his property, when Reuven says that he might also be a Shechiv-Mera (on his death-bed).

Not so obvious is the Din in a case where he declares 'Tenu Cheilek li'Peloni'. Besides possibly a half, Chelek might mean a portion (which Beis-Din would then have to assess).

Initially, Ravina (or Rava) bar Kisi reconciles this with the Beraisa 'Tenu Chelek li'Peloni bi'Nechasai', Yirash im ha'Banim' by establishing our case where the donor has no sons (because it is only when he has sons that we assume the Chelek of the stranger to be a small portion. Whereas there where he has none, perhaps it means half).

True, there are other heirs (because every Yisrael has relatives) but still, one tends to be less concerned about other heirs than about one's own children.

One of the alternative explanations is that the Amora'im who asked the She'eilah and Ravina bar Kisi, were not aware of that Beraisa (even assuming that we are speaking where the donor has children). Bearing in mind that we are about to cite Sumchus to resolve the She'eilah, they might even have known of the Beraisa, but declined to cite it because the author is the Rabanan of Sumchus, and we rule like Sumchus (though many commentaries disagree with this explanation).

Ravina bar Kisi cites the Beraisa 'ha'Omer Tenu Chelek li'Peloni be'Bor, Ein Pachos me'Revi'a'. The Tana is speaking about a water-pit (see Rabeinu Gershom), although some establish it by a wine-pit.

Sumchus, the author of this Beraisa, issues this ruling in keeping with his own opinion in Bava Kama 'Mamon ha'Mutal be'Safek, Cholkin'. 'Ein Pachos me'Revi'a' implies a little more than a quarter of the pit, because the Safek here, is not whether the recipient receives a half or nothing, but a half or a small portion (e.g. a Perutah's-worth); So he receives a half of his claim.

Sumchus continues 'le'Chavis, Ein Pachos mi'Sheminis'. The significance of the eighth is that a barrel would normally hold half the water in the pit (so the quarter of the pit of the previous case becomes an eighth).

Sumchus rules that if the donor said 'for the pot', the recipient will not receive less than a twelfth (a quarter of a third of the pit) because Chazal knew that a third of the pit was generally needed for the pot.

And if he said 'li'Tefi'ach' (a small earthenware vessel used for drinking), he concludes, the recipient receives not less than a sixteenth (a quarter of a quarter).

According to some commentaries, Sumchus' Shiurim are based on the Chachamim's assessment of what the donor probably meant to give.

The Beraisa states that if Levi sells a field to a Yisrael on condition that he receives the Ma'aser each year his condition is valid, and the purchaser is obligated to give him all the Ma'aser each year.

If the purchaser sells the field nothing changes, because the seller only sold the rights that he owned, but not the Levi's (which were not his to sell).

The Levi's son will inherit his rights only if he made a stipulation to that effect, but not otherwise.

The Tana rules that if the Levi stipulates that the Ma'aser is his only as long as the field is in the purchaser's jurisdiction then should the purchaser subsequently sell the field and buy it back, the Levi no longer has any rights to the field (because the second purchaser purchased the rights of Ma'aser with his purchase, and he sold them back to the first purchaser together with the field).

We query this Beraisa however, on the grounds that the Ma'aser is a 'Davar she'Lo Ba L'Olam' (seeing as the field has yet to be plowed, let alone sown), and we have a principle that one cannot acquire a 'Davar she'Lo Bo L'Olam' (something that is not yet in the world).

We answer that seeing as the Levi made a stipulation, he obviously wants it to take effect. So we assume that he held back the small portion of land sufficient to separate Ma'aser from it (and the land is a Davar she'Ba l'Olam [though this is very difficult to understand, since no land is specified, and to rely on the land from which the Ma'aser will later be separated will involve the question of 'Bereirah'!]).

Reish Lakish extrapolates from this Beraisa that if someone sells a house on condition that the top story (i.e. the roof including a Ma'akeh) remains his, his condition is effective.

The basis of his Chidush (the details of which we are about to discuss) is the fact that as far as using the roof is concerned, we already learned in our Mishnah that the roof is not included in the sale (and no stipulation is therefore required).

Rav Zvid explains Reish Lakish (who, based on the Beraisa, validates the seller's condition that the roof including a Ma'akeh remains his, as we just explained) to mean that if he wants to fix ledges that jut out over the purchaser's Chatzer, he may. If not for the condition this would not have been included in his rights.

In the event that the seller dies this right does not extend to his children, unless he stipulated that it should (as we learned above with regard to Ma'aser).

According to Rav Papa, the condition does not permit the seller to fix ledges that jut out over the purchaser's Chatzer. What it does achieve is to permit him to rebuild the roof should it collapse ...

... and the Mishnah in Bava Metzia, which permits the owner of the roof to rebuild it should it cave in, even without any conditions speaks about two partners who divided their joint house, one taking the downstairs apartment, the other, the upstairs. In that case, it is understood that the owner of the upstairs apartment receives the same permanent rights as the owner of the downstairs one.

Rav Zvid disagrees with Rav Papa (which is basically the smaller Chidush, as we shall see shortly) on the grounds that the seller initially thinks of the immediate benefit of fixing ledges to his roof, but not of the possible eventuality that his roof might cave in.

The problem with Rav Papa's interpretation of Reish Lakish's Chidush is what it has to do with the Beraisa of Ma'aser (from which Reish Lakish extrapolated it), since the Beraisa is referring to the seller holding back space for himself (a Chidush with which Rav Zvid's interpretation of Reish Lakish tallies), and not with time (as he explains Reish Lakish).

Even without Reish Lakish, we would have known Rav Papa's Chidush from Rebbi Akiva in the following Mishnah, from whom we learn that every stipulation comes to add something (incorporating a time extension). An extension of space, it seems, we would not have known without the Beraisa, as Reish Lakish teaches us according to Rav Zvid's interpretation).

We are not able to answer the Kashya on Rav Papa.

According to Rav Dimi from Neharda'a, if Reuven sells Shimon a house and he specifically includes 'Umka ve'Ruma' ...

... 'Umka' incorporates the ground itself vis-a-vis digging pits underneath his house.

... 'Ruma' incorporates the roof even if it has a Ma'akeh of ten Tefachim, as well as the air above the roof, entitling him to build more floors should he so wish.

According to Rav Dimi, if he wants to include a Bor and a Dus, he must add 'mi'Tehom Rabah ad Rum Raki'a', because they serve a completely different purpose than the house itself (as we have already explained), and are therefore not even included in 'Umka ve'Ruma'.

This Lashon also includes Mechilos (tunnels).

We try to prove from the next Mishnah 've'Lo es ha'Bor ve'Lo es ha'Dus, Af-al-Pi she'Kasav lo Umka ve'Ruma' Rav Dimi's ruling (that 'Umka ve'Ruma does not include Bor va'Dus u'Mechilos).

We refute the proof however by establishing it where he did not actually write Umka ve'Ruma in the Shtar.

And when the Tana writes 'Af-al-Pi she'Kasav lo ... ', he means that even though he did not insert it, it is as if he actually did write it.

'Umka ve'Ruma' will then come to include Umka ve'Ruma, and no more, just as we explained a little earlier.

We again try to prove Rav Dimi right from our Mishnah 've'Lo es ha'Gag bi'Zeman she'Yesh lo Ma'akeh Gavohah Asarah Tefachim', because, if we assumed that one acquires Umka ve'Ruma (including the roof) automatically why would the fact that the roof had a Ma'akeh of ten Tefachim make any difference?

If on the other hand, one does not acquire Umka ve'Ruma automatically (like Rav Dimi), there is no problem with the fact that the purchaser nevertheless acquires the roof-space when there is no Ma'akeh because it would be Batel to the house (just like an attic).

We refute this proof too however on the grounds that a roof with a Ma'akeh might be different, inasmuch as it is Chashuv, and can therefore be considered a separate entity, even if a roof without a Ma'akeh is considered part of the house.