ANNULMENT OF A YEVAMAH'S VOWS
(Mishnah - R. Eliezer): The Yavam can annul vows of a Shomeres Yavam, whether there is one Yavam or two;
R. Yehoshua says, if there is one Yavam, he can annul her vows. If there are two, neither can annul them;
R. Akiva says, whether there is one Yavam or two, he cannot annul her vows.
R. Eliezer: If a husband can annul the vows of a woman that he chose to marry, all the more so he can annul vows of a woman that Shamayim acquired to him (i.e. through the death of his brother)!
R. Akiva: No. A husband can annul his wife's vows because she is special to him and to no one else. You cannot learn to a Yevamah, for others (other Yevamim) have a connection to her!
R. Yehoshua: Akiva, your objection applies only when there are two Yevamim, not when there is only one!
R. Akiva: A Yevamah is not acquired to her Yavam as fully as a wife is to her husband.
(Gemara) Question: Granted, R. Akiva holds that Ein Zikah (a Shomeres Yavam is not considered to be partially married to the Yavam);
Granted, R. Yehoshua holds that Yesh Zikah;
Question: What is R. Eliezer's reason?
Even if he holds that Yesh Zikah, there is not Bereirah (retroactive clarification. I.e., we cannot say that now she is already considered partially married to the Yavam who will later do Yibum!)
Answer (R. Ami): The case is, Reuven (a Yavam) gave to her a Ma'amar (Kidushin of a Yevamah). R. Eliezer holds like Beis Shamai, who say that a Ma'amar fully acquires her.
R. Yehoshua holds that this applies only when there is one Yavam;
It is unreasonable that Shimon (Reuven's brother) could have Bi'ah with her or give a Get to her, which would forbid her to Reuven, and Reuven can annul her vows!
R. Akiva holds that Ein Zikah.
Question: R. Elazar (ben Pedas, an Amora) holds that Beis Shamai say that a Ma'amar does not fully acquire a Yevamah. It merely eliminates Zikah to the other brothers. How can he explain R. Eliezer?
Answer: The case is, Beis Din ruled that the Yavam must feed her. (E.g. one Yavam went away, she took the remaining Yavam to Beis Din, and he fled.) R. Eliezer holds like Rav Pinchas:
(Rav Pinchas): Every woman intends that her vow be valid only if her husband will consent to it.
Question (against R. Ami - Mishnah - R. Eliezer): A husband can annul vows of a woman whom he chose to marry. All the more so, he can annul vows of a woman whom Shamayim acquired to him!
If he gave to her a Ma'amar, he acquired her himself!
Answer: He acquired her himself, through the hands of Heaven.
DOES A MA'AMAR MAKE NISU'IN?
Suggestion: We can resolve Rabah's question:
Question (Rabah): According to Beis Shamai, does a Ma'amar make Kidushin or Nisu'in?
If it makes only Kidushin, he would not be able to annul!
(Mishnah): The vows of a Na'arah Me'orasah can be annulled by her father and Arus (together).
Rejection (Rav Nachman b'Rebbi Yitzchak): We can say that it makes Kidushin. R. Eliezer said that he can annul, i.e. together with the father.
A Beraisa supports R. Ami.
(Beraisa - R. Eliezer): Whether there is one Yavam or two, the Yavam can annul vows of the Shomeres Yavam;
R. Yehoshua says, if there is one Yavam, he can annul. If there are two, they cannot annul;
R. Akiva says, in either case he cannot annul.
R. Eliezer: A (standard) wife was not acquired at all to her husband before he was Mekadesh her. After marriage, the Kinyan is completed (and he can annul her vows). A Yevamah was partially acquired to her Yavam before he acquired her. All the more so, when she enters his Reshus, the Kinyan is completed!
R. Akiva: You cannot learn from a husband, for just like he had no attachment to her (before Kidushin), no one else did, either. A Yevamah was partially acquired to her Yavam by Shamayim. She was also partially acquired to other (Yevamim)!
R. Eliezer: R. Akiva, your objection applies only when there are two Yevamim, not when there is only one!
R. Akiva: We do not distinguish (regarding other laws) whether there is one Yavam or two, or whether or not he gave a Ma'amar. Annulment of vows is like other laws!
Ben Azai: It is a shame that I did not serve a Chacham like R. Akiva (to learn from him)!