Question (R. Yudan): According to the opinion that all agree that he is liable for the Tzarah, if a stranger from the market was Mekadesh one of them, and the Yavam did Chalitzah to her and then had Bi'ah with her, the [first] Kidushin is uprooted [it did not take effect fully when she was Zekukah, and now the Choletz' Kidushin takes effect, for only a Lav forbids her]. If he did Chalitzah to one of her Tzaros and had Bi'ah with her (the one who accepted Kidushin, she is forbidden to him with Kares. Will you say that) the Kidushin takes effect retroactively?! (It is unreasonable to distinguish like this!)

Answer (R. Shamai): Didn't R. Yanai say that more than 30 Chachamim voted, and said 'what is the source that Kidushin does not take effect on a Yevamah? "Lo Sihyeh Eshes ha'Mes ha'Chutzah l'Ish Zar" - she cannot have Havayah (Kidushin) with someone else. (In both cases the Kidushin is Batel. We explained this like MEICHAL HA'MAYIM.)

(R. Yochanan): Doesn't a Mishnah teach this? [If one told a woman 'you are Mekudeshes to me...] or after your Yavam does Chalitzah to you', she is not Mekudeshes (since Kidushin does not take effect on her now, this is Davar she'Lo Ba l'Olam).

R. Yanai praised [R. Yochanan's proof] - 'ha'Zalim Zahav mi'Kis", "Bni Al Yalizu me'Einecha", "Chacham Bni v'Samach Libi", "Ten l'Chacham v'Yechkam Od", "Yishma Chacham v'Yosef Lekach."

Objection (Reish Lakish): After all these praises [it is not a solid proof]. We can establish the Mishnah like R. Akiva, for R. Akiva says that there is a Mamzer from a Yevamah l'Shuk! (However, Chachamim could say that there is Kidushin in a Yevamah, if not for R. Yanai's Drashah above.)

Question: [We cannot learn from R. Yanai's Drashah. Perhaps the verse discusses when] there is [only] one Yevamah (she is Vadai Zekukah), and here (in R. Yudan's question) there are two Yevamos!

Question: Is there any difference between the Isur of one Yevamah and the Isur of two Yevamos?! (The Torah did not distinguish. Surely they are the same!)

Question (R. Yudan): According to the opinion that all agree that he is not liable for the Chalutzah, but the brothers are liable for the Chalutzah, Chalitzah exempts [from Zikah], and Bi'ah exempts;

Just like you say that if he did Chalitzah to her, she is forbidden to the brothers [and there is Kares], you should similarly say that if he had Bi'ah with her, she is forbidden to the brothers;

[However,] R. Chiyah taught that if the first brother died and the second did Yibum and the second died, the third does Yibum!

Answer (R. Yosi): Do you think that Chalitzah is [just like] Bi'ah? (It is not!)

Once he did Chalitzah to her, Zikah is uprooted from her retroactively, and retroactively the Isur of [Eshes] ha'Mes takes effect on the brothers. However, if he did Bi'ah, she is his wife!

(R. Chiyah): If the first brother died and the second did Yibum and the second died, the third does Yibum.