(Rav Huna bar Avin, R. Avin...): If Reuven bought land from a Nochri and Shimon dug a little in it; we do not take the land from Shimon.

(Rabah citing Shmuel): The law of the kingdom is binding;

In Persia, a Nochri makes a Chazakah after 40 years (if Levi buys from a Nochri who has such a Chazakah, Yehudah cannot claim 'the land was stolen from me');

If one pays (to the king's officials) the tax due on another's land to receive the land, he acquires it.

This is only if the land is sold for the land tax. If it is sold for the head tax (that the owner owed, this is not the law of the kingdom), the sale is invalid.

Question: What is the reason?

Answer: The head tax is a personal liability. It is unrelated to the land.

(Rav Huna brei d'Rav Yehoshua): No, the sale is valid. The head tax creates a lien even on Peros that were harvested and put in a Keli!

Question (Ameimar): If so, a firstborn does not get a double portion (if his father had not yet paid the head tax for this year), for the father was not Muchzak in his land. Whoever paid the tax would receive it!

A firstborn gets a double portion only in property Muchzak to the father, but not if the father was merely apt to receive it.

Counter-question (Rav Ashi): Also according to you (that only the land tax creates a lien), if this year's land tax was not yet paid, a firstborn does not get a double portion!

Answer (Rav Ashi): You must say that a firstborn gets a double portion when the father already paid the land tax;

Answer (Rav Ashi): Likewise, Rav Huna brei d'Rav Yehoshua holds that he gets a double portion when the father already paid the head tax.

(Rav Ashi): Rava's scribes said that the Halachah follows Rav Huna brei d'Rav Yehoshua.

Rejection: The Halachah is not like him. They said so to defend the documents they wrote (for sales due to non-payment of the head tax).

(Rav Ashi): An utterly idle man (he does not work or learn) must pay a share of taxes imposed on the city (even though he does not earn money in the city);

This is only if the king's tax collectors asked him to pay, and people of the city convinced the tax collectors that he is unable, and therefore more was collected from the other residents;

If the tax collectors never asked him to pay, this shows that Hash-m exempted him!

(Rav Asi): A fence or Chatzav (tree) divides a Hefker field (i.e. Chazakah on one side does not acquire the other side), but they are not divisions regarding Pe'ah or Tum'ah (as will be explained).

(Ravin): They are divisions also regarding Pe'ah and Tum'ah;

Question: What difference does it make regarding Pe'ah?

Answer (Mishnah): The following are a division for Pe'ah (they obligate leaving a separate Pe'ah on each side): a Nachal (Rashi - valley; Rambam - river; Rashbam - rocky area), a Shelulis (irrigation ditch; some explain, a pond), a public or private road, or a public or private path that is used in winter and summer.

Question: What difference does it make regarding Tum'ah?

Answer (Mishnah - R. Elazar): If Reuven entered a valley in winter, and there was Tum'ah in one field in the valley, and Reuven does not know whether he entered that field, he is Tahor;

Chachamim say, he is Tamei (this is Safek Tum'ah in a Reshus ha'Yachid (Reshus ha'Yachid)).

R. Elazar says that a Safek about touching Tum'ah is Tamei, but here we are unsure whether he even entered the place of Tum'ah. (Rashi - we learn (from Sotah) only that Safek Tum'ah is Tamei when he surely entered the place of Tum'ah; Rashbam - we have a double Safek. Perhaps he did not enter, and even if he entered, perhaps he did not become Tamei.)

(Ravin): Regarding Shabbos, a fence or Chatzav does not divide a field.

(Rava): Also regarding Shabbos, a fence or Chatzav divides a field.

(Beraisa): If Reuven took half a fig (on Shabbos, b'Shogeg, from a Reshus ha'Yachid) to a Reshus ha'Rabim and put it down, and then brought another half fig to a Reshus ha'Rabim: if he remembered in between that this is forbidden, he is exempt (from bringing a Korban). If not, he is liable.

R. Yosi says, if he took both halves to the same Reshus ha'Rabim, he is liable. If not, he is exempt.