Rambam - 1 Chapter a Day

See Hilchot Zechiyah UMatanah 1:6.

See Halachah 4.

The manner in which the property must be divided is discussed in Chapter 2, Halachot 14-18.

For each person will not receive a share large enough to be of benefit to him.

The Meiri in his commentary on Bava Batra 11a gives examples of such a situation: two brothers inherit a property, but their testator clearly specifies which portion of the field each one is to receive; two partners buy a property that was divided between two separate owners.

According to the Rambam, the principle to be explained applies with regard to all the types of partnership mentioned in the previous halachah. The Ra’avad differs and maintains that it does not apply when two people bought a property in partnership, because the party who did not desire to divide the property could say to the other: “We did not enter into the partnership with such an understanding.”
The Maggid Mishneh supports the Rambam’s ruling, explaining that the other partner could explain that at the beginning he thought that the partnership would be harmonious, and now he finds it difficult to deal with his partner.

From the Rambam’s words here, it appears that the person can arbitrarily fix the price. From the Rambam’s Commentary on the Mishnah (Bava Batra 1:6), it appears that the person must be prepared to buy and sell at the property’s market value. Note the gloss of the Maggid Mishneh, which touches on this issue. The Tur and the Ramah (Choshen Mishpat 171:6) follow the Rambam’s wording here. Note, however, Halachah 5, which speaks of assessing the value.
The above applies to a price that is more than the property’s market value. A partner cannot employ this principle and offer a price lower than that of the market value. If that were possible, a rich man would take advantage of a poorer man on every occasion [Beit Yosef; Ramah (op. cit.)].

Rashi, Bava Batra 13a, offers a different interpretation, stating: “Either quote a price at which you desire to purchase my share, or I will quote a price at which I desire to purchase your share.” The Shulchan Aruch (op. cit.) quotes the Rambam’s words.

This principle is referred to by Bava Batra 13b with the term gud o agud - “Acquire or I will acquire.”

Our translation follows the commentary of the Maggid Mishneh, who explains that the definition of “made for the purpose of hire” or “made for his personal use” is functional: what the structure is most suited for. This interpretation is also borne out by the Rambam’s ruling at the conclusion of the halachah.
The Kessef Mishneh offers a different interpretation, explaining that the fundamental question is: What was the father’s intent when dividing the property among his heirs?

The rich brother cannot say: “Let each of us rent out our own portions separately,” for such properties are usually rented out as a total unit (Ramah, op. cit.).
The Maggid Mishneh and other commentaries state that if the either brother desires, he can employ the ultimatum of gud o agud and compel the other brother to sell him his share.

Thus, although the poor brother does not receive any benefit from the property, the rich brother is under no obligation to him.

I.e., the property as a whole. Alternatively, he can sell his portion of the property to another rich person who would be able to use it in partnership with his brother (Sefer Me’irat Einayim 271:14).

The Tur and the Ramah (loc. cit.) differ and maintain that if the person does not want to purchase the property for himself, he cannot employ the principle gud o agud. All authorities agree, however, that an heir may borrow to purchase the entire property.

The exact term the Rambam uses to refer to the invasion of privacy, hezek r’iyyah, is defined in Chapter 2, Halachah 14.

The Ra’avad differs with the concept of dividing the use of the property over time, explaining that even if the period for rotation is protracted, it is still undesirable. Instead, the involved parties should be compelled either to accept the invasion of their privacy or to divide the property physically.
The Maggid Mishneh supports the Rambam’s position, explaining that the invasion of property is a totally untenable proposition: Should two married couples share the same bedroom? Nor is the division of a property that is not large enough to divide feasible, for then the portion of the property that each partner would receive would not be of benefit to him.
With regard to a home, the opinion of the Maggid Mishneh is accepted. With regard to a courtyard, however, the Ramah accepts the Ra’avad’s logic.

This phrase applies both to the field and to the courtyard.

The Rambam maintain that the principle of gud o agud applies even with regard to rented property. As mentioned above the Ra’avad differs and maintains that this principle applies only with regard to property received through an inheritance or a gift, for in these situations the two people had no control over whether they became partners. With regard to property purchased or rented in partnership, each of them willingly entered into the partnership and therefore cannot dissolve it at will.
As explained above, the Maggid Mishneh explains the Rambam’s position as follows: At the outset, the person thought that he would appreciate the partnership. As time passed, it became uncomfortable. Therefore, he has the right to dissolve it. The Shulchan Aruch (Choshen Mishpat 171:9) quotes the Rambam’s view.

For, as evident from the previous halachot, it is preferable to divide a property rather than to compel one of the partners to buy the other’s portion according to the principle of gud o agud.
The Tur and the Ramah question the Rambam’s ruling, asking: How is it possible for renters to construct a divider in a rented property?

Implied is that when there was a three-way partnership, with two partners each owning 40% and the third only 20%, even if the division would afford the partners with the larger share a portion of the property that is significant, should the partner with the smaller portion not receive a significant portion, he may nullify the division (Sefer Me’irat Einayim 171:5).

In his Commentary on the Mishnah (Bava Batra 1:6), the Rambam explains that this area is granted in addition to the area of four cubits that is granted to every homeowner in a courtyard so that he can load and unload packages before his entrance.
Furthermore, as will be explained in the notes on Chapter 2, Halachah 1, this applies only with regard to courtyards in country villages, where courtyards are used to pasture animals. Courtyards in a city are divided even if each person will receive a smaller portion of land.

3750 square cubits [Rambam’s Commentary on the Mishnah (op. cit.)].

I.e., it would not be worth the effort to plow, irrigate and do any other work necessary for a field unless it were at least this size.

Where vegetables are grown, and hence a smaller size is also valuable.

Slightly more than 208 square cubits.

1250 square cubits.

I.e., countries where land is scarce and very valuable.

Similarly, all the other measures require a day of work. Sefer Me’irat Einayim 171:8 explains that such a measure was chosen because a worker would not be willing to accept a job that requires less than a day of work.

I.e., in contrast to the field mentioned previously, which is watered by using irrigation ditches. This type of field parallels the garden mentioned with regard to Eretz Yisrael.

See Hilchot Mechirah 21:5, which defines the minimum size of a hall as ten cubits by ten cubits.

I.e., the principle of gud o agud explained above.

I.e., the person is proposing that the other partner be given the minimum size required for the entity, and he would receive the remainder. For example, if a courtyard was seven cubits by four cubits, the partner making the suggestion would receive three cubits by four cubits, and the other, four cubits by four cubits.

For, as stated in Proverbs 15:27 and quoted at the conclusion of Hilchot Zechiyah UMatanah: “One who hates gifts will live.”
When stating this law, the Shulchan Aruch (Choshen Mishpat 171:10) also states that one party cannot compel the other to pay the difference in value between the two portions. The Shulchan Aruch also mentions a differing opinion, which gives one partner the right to compel the other in this regard.
The Shulchan Aruch also mentions that one party may tell the other: “Let us divide the field, and either I or you will pay for the extra portion. If you do not consent to such a division, I will purchase the entire field.”