daf bit: Bava Batra 104

[cellio]

The talmud discusses land sales where the land area represented by the seller is not quite accurate. If he overstated the size of the parecel he must return a proportion of the buyer's money, but if he under-stated the size there is discussion of whether the buyer pays the difference or the seller keeps the extra land. Usually the buyer buys the extra, but if the field being sold is adjacent to another owned by the seller, the seller instead keeps the extra because he can extend his own field to make use of it. The g'mara then questions the definition of "adjacent": does a water cistern between the two parcels form a division (making them not adjacent)? If not, what about a canal? If not, what about a public road? These matters are unresolved. (104b)

(If I understand correctly, all unresolved matters in the talmud are left for Eliyahu to settle when he comes back with the moshiach (messiah).)