Gemara

Keti'a bar Shalom declared 'my property is given to R. Akiva and his colleagues.'

R. Akiva: "V'Haysah l'Aharon ul'Vanav" teaches that Aharon gets half, (of the Lechem ha'Panim), and his sons (the other Kohanim) get half. (Here also, I get half, and my colleagues get half.)

Bava Basra 142a (Rav Yosef): If Yakov told his wife 'my property is to you and your sons', she gets half, and her sons get half. We learn from the following Beraisa.

(Beraisa - Rebbi): "V'Haysah l'Aharon ul'Vanav" - Aharon gets half, and his sons get half.

Objection (Abaye): There, had the verse not mentioned Aharon, he would have received a share. Surely, he is mentioned to teach that he gets half;

Normally, a wife does not inherit. Yakov mentioned her to teach that she gets a share like her sons!

Question #1 (against Abaye): Cases occurred, and Shmuel and R. Yochanan ruled that she gets half!

Question #2: Rav Yitzchak bar Yosef taught that once, the king demanded that the rich people and the (less rich) nobles buy a crown for him. Rebbi ruled that the rich pay half, and the nobles pay half!

Answer (to Question #2): Initially, the king wrote only that the rich must pay. The nobles used to help a small amount. When the king found out, he included the nobles to (increase the demand and) teach that each group pays half.

Question (against Rav Yosef - R. Zeira - Beraisa): If one said 'it is upon me to bring a flour-offering of 100 Esronim in two Kelim', he brings 60 in one Keli, and 40 in another Keli. If he brought 50 in one Keli and 50 in another Keli, he fulfilled his obligation.

This is only b'Di'eved. According to Rav Yosef, l'Chatchilah he brings half in each!

Answer: There, he clearly intends to bring a big Korban. He specified to bring in two Kelim, because he knows that he cannot bring it all in one Keli. He should bring as much as is possible (60) in one Keli.

The Halachah follows Rav Yosef.

33a: Rav Idi bar Avin's relative died, and left a date tree. Rav Idi and another relative (Reuven) each said 'I am the closer relative.'

Rishonim

Rambam (Hilchos Zechiyah 11:5): If one said 'my property is to Ploni and my sons', Ploni gets half, and all his sons get half. A case occurred in which a man told his wife 'my property is to you and your sons', and Chachamim said that she gets half, and her sons get half.

Hagahos Maimoniyos (4): A man and his wife stipulated that if one of them dies, the property will go to their relatives. My Rebbi ruled that the relatives of the deceased get half. Since the couple did not specify a person, his relatives acquired half and her relatives acquired half. They cannot change this, even to give from one Ani to another, and even if one has more relatives than the other.

Rambam (6): If he said 'I give to Ploni, Almoni, and David's sons', David's sons get half, and Ploni and Almoni get half.

Rebuttal (Ra'avad): If he said 'to Ploni and Almoni and David's sons', David's sons should get a third, just like if he said 'to Ploni and Almoni and David! The same applies if he said 'to Ploni and to Almoni and to David's sons.' However, if he said 'to Ploni and Almoni and to David's sons, then the Rambam's law is correct, for he made Ploni and Almoni one group, and David's sons are one group.

Magid Mishneh: The Ramban holds that the group always gets half. The Ramban says that the group always gets like one of the individuals, for if not, sometimes people in the group get more than the individuals, e.g. if he said give to Reuven, Shimon, Levi and Yehudah's sons, and Yehudah has only two sons, the two sons get half. The Ra'avad's distinction (based on to whom he said 'to') is as fine as a hair's width.

Rosh (Bava Basra 9:7): If the giver listed many people and a group, the group gets half, even if has less people than were listed. E.g. if one said 'I give to Ploni, Almoni, David, and Reuven's sons', even if Reuven has only two sons, the two sons get half.

Nimukei Yosef (Bava Basra 66b DH v'Im): The Gemara connotes that there is importance to the individual. The Rashba and Ro'oh hold like the Ramban. The Ritva received from his Rebbi that this is not limited to gifts. It applies also to one who says 'lend to Ploni and Almoni and their children', and to any stipulation and agreement of an individual or Tzibur.

Poskim

Shulchan Aruch (CM 247:5:): If one said 'my property is to Ploni and my sons', Ploni gets half, and all his sons get half. If he said 'I give to Ploni, Almoni, and David's sons, David's sons get half, and Ploni and Almoni get half. This is even if he listed more individuals than are in the group, e.g. he said 'I give to Ploni, Almoni, David, and Reuven's sons, and Reuven has only two sons.

Beis Yosef (DH u'Mah she'Chosav): The Ran (143a DH ha'Hu) says that Rav Yosef does not say that the individual gets half due to his importance, i.e. since he was singled out, the giver esteems him as much as the group. If so, what was the question from a Minchah of 100 Esronim? There, he did not list the Kelim individually to show that he esteems them! Rather, Rav Yosef holds that one wants to divide his property according to his words. Since he made two divisions with his words, we give half to each division. Therefore, if he said 'my property is to Reuven, Shimon and Ploni's sons', Reuven and Shimon get half, and Ploni's sons get half. If he listed three individuals, and Ploni had only two sons, the individuals get less than the sons. This is because they do not get half due to their importance. This is like the Rambam; the Ramban says that the group always gets like one of the individuals. It seems that he holds that (when there is one individual,) he gets half due to his importance.

Rema: The same applies to other matters. Therefore, if a man and wife stipulated that if one of them dies, the property will go to their relatives, his relatives get half and her relatives get half.

Ketzos ha'Choshen (2): The Ritva (143b) says that 'my relatives' includes all relatives disqualified from testifying for him. Tosfos (Bava Basra 33a DH Krivei and DH Hachi) brings a text that connotes that Rav Idi's relative commanded to give the tree to 'Krivei' (his relative(s)), there was a dispute about who is closest. This shows that we do not give it to all the relatives, rather, to the closest one! He brings another text that does not say 'closer.' One text says that later, witnesses testified that Reuven was a relative, i.e. disqualified from testimony. Rav Idi could not prove that he himself was close enough to be disqualified. Reuven received the entire tree, for a Safek cannot take from a Vadai.

Nesivos ha'Mishpat (Urim 5): The Beis Yosef says that all the relatives (that the Torah disqualifies for testimony) divide it equally.

R. Akiva Eiger: Panim Yafos (Sefer ha'Makneh's Perush on the Torah) Parshas Emor was unsure whether this is only for gifts, or even for sales.

Terumas ha'Deshen (Pesakim 73): Rava holds like R. Yonason, who normally expounds 'Vov' to mean 'or.' Presumably, the Halachah follows him against Abaye, who rules like R. Yoshiyah (who says that it means 'and'. Here, there was no Hava Amina that the Lechem ha'Panim goes to Aharon or his sons (e.g. they cast a lot to decide), for the verse concludes "they will eat it in a Kodesh place.

Chasam Sofer: The Ritva (citing R. Pinchas ha'Levi, in Shitah Mekubetzes Bava Metzia Sof 94b) says that R. Yonason agrees (that 'Vov' means 'both) regarding a command to do or give. Yoma 57b refutes this (R. Yonason holds that the blood of the bull and goat are placed separately).