(Mishnah): If Reuven did Chalitzah with Leah and then his brother married her sister, and he died, Reuven does Chalitzah, but not Yibum;

Similarly, if Reuven divorced his wife and then his brother married her sister, and he died, the widow is exempt (from Chalitzah and Yibum);

Question (Shimon bar Ba, to R. Yochanan): What is the difference between one who does Chalitzah (when her sister falls to him for Yibum, she needs Chalitzah) and one who divorces (when her sister falls to him, she is exempt)?

Answer (R. Yochanan): Do you think that Chalitzah is a Kinyan (it is as if he married her, and divorced her?! It is not) It is only an exemption;

The other brothers are not liable for [the Chalutzah] because she was the wife of the Choletz, but they are liable for her because she was the wife of the Mes. (Therefore, if we consider the Choletz to be a Shali'ach of the brothers, they are liable for her only for a Lav (Lo Yivneh), but not Kares.)

(Mishnah - R. Yehudah ben Beseira): If Reuven was Mekadesh the sister of his Yevamah, we tell him to wait until his brother (Shimon) does Yibum or Chalitzah. After that, Reuven may make Nisu'in;

If the Yevamah died, he may make Nisu'in. If Shimon died, Reuven divorces his wife and does Chalitzah to his Yevamah.

(Gemara): They said only that if the Yevamah died, he is permitted to his wife, but if his wife died, he is forbidden to his Yevamah.

(R. Yochanan): This is R. Lazar's opinion, but Chachamim say that if the Yevamah died, he is permitted to his wife. If his wife died, he is permitted to his Yevamah.

(R. Yochanan): Chachamim say that any [Isur] due to a cause, when the cause is Batel, the Isur is Batel. R. Lazar says that even though the cause is Batel, the Isur remains.

(Mishnah): A Yevamah may not do Yibum or Chalitzah until three months [from the death of her husband].

Similarly, no woman may become Mekudeshes or married for three months, whether or not she is a virgin, whether she was divorced or widowed, from Nisu'in or Kidushin;

R. Yehudah says, if she was only Mekudeshes she may get married. If she was married, she may become Mekudeshes, except for an Arusah in Yehudah, since [the Arus] is intimate with her (they are secluded; perhaps they had Bi'ah).

R. Yosi says, all women may become Mekudashos [immediately], except for but a widow, due to Aveilus (mourning over her husband).

(Gemara) Question: How long is until the fetus is recognized?

Answer (Sumchus citing R. Meir): It is until three months. Even though there is not a proof, there is a hint - "va'Yhi k'Mishelosh Chadashim" (and then they told Yehudah that Tamar is pregnant).

(R. Yudan): Even if she is pregnant with Ru'ach (there is no baby inside, it is not recognized until three months) - "Harinu Chalnu Kemo Yaladnu Ru'ach", "Taharu Chashash Teldu Kash" (it is called pregnancy and birth).

(R. Ze'ira citing R. Ba bar Zutra citing R. Chaninah citing R. Chiyah Ruba): Even the majority of the first month, the majority of the last month, and the entire middle month (is enough to recognize the fetus);

(Rav Asi): Ninety full days are required.

(Shmuel): They and their Ibur are needed (each month counts like 29 or 30, depending on which day was made Rosh Chodesh).

A case occurred in front of Rabanan there (in Bavel, of a woman whose husband was away for more than three months, and she gave birth six months after he returned). We do not know if there were 13 [days] from the first [month] and 17 from the last, or 17 from the first and 13 from the last, and five full [months] in the middle. They wanted to consider the child a Safek Mamzer (it is likely that he was not from her husband);

Rav Nachman bar Yitzchak told them, such a case came in front of Rabah bar Ba, and he was Machshir.

Aba bar Va (this is Rabah bar Ba) argues with his son Shmuel.

Rebuttal (Rava): (No.) The time needed to recognize the fetus] is unlike [the time needed for] birth. Recognizing the fetus is after [three] full months. Birth is after [seven or nine] truncated months.