DOES MA'AMAR MAKE NISU'IN?
Question: How does this Beraisa support R. Ami?
Answer #1: R. Akiva responded, '... whether or not he gave a Ma'amar.' This shows that R. Eliezer discusses a case in which he gave a Ma'amar!
Answer #2: R. Eliezer said when she enters the Yavam's Reshus, the Kinyan is completed.
If she was not already partially acquired through a Ma'amar, it is inappropriate to say that the Kinyan is completed. We must say that he gave to her a Ma'amar.
Question: What does it mean 'vows are like other laws'?
Answer (Rava): She is not considered Mekudeshes regarding stoning (if she has Bi'ah with a stranger, whether there was one Yavam or two, whether or not a Ma'amar was given. Also, regarding vows she is not considered Mekudeshes.)
Support (Rav Ashi - Mishnah): A Yevamah is not totally acquired to her Yavam like an Arusah is to her husband.
ANNULMENT IN ADVANCE
(Mishnah): If a man told his wife (Leah) 'all vows that you will make from now until I return from Ploni (a certain place) are affirmed', this has no effect;
R. Eliezer says, if he says 'they are annulled', they are annulled;
Chachamim say, they are not.
R. Eliezer: If he can annul vows that already took effect, all the more so, he can annul vows that did not yet take effect!
Chachamim: "Her husband will affirm it, her husband will annul it" - only a vow that can be affirmed (i.e. has already taken effect) can be annulled.
(Gemara) Question: According to R. Eliezer, do the vows take effect and then they are annulled? Or, do they not take effect at all?
This determines the law if Levi vowed 'this is forbidden like what Leah forbade.'
Levi's vow also takes effect only if Leah's vow took effect.
Answer #1 (Mishnah - R. Eliezer): If he can annul vows that already took effect, all the more so, he can annul vows that did not yet take effect!
This shows that they do not take effect at all.
Rejection: The Mishnah does not say 'they do not take effect', rather, they did not yet taken effect!
Answer #2 (Beraisa - R. Eliezer): A man cannot annul his own vows after he vowed, but he can annul them before he vows;
Regarding his wife's vows, which he can annul after she vowed, all the more so he can annul them before she vowed!
Assumption: His vows are like his wife's. Just like his do not take effect, also his wife's.
Rejection: No, they are different. His don't take effect, but his wife's do.
Answer #3 (Beraisa - Chachamim): We find that a Mikvah makes a Tamei (person or Kli) Tahor, but it does not save a Tahor person from becoming Tamei (afterwards);
A person cannot be Metaher a Tamei, all the more so, he cannot save a Tahor person from becoming Tamei (i.e. that her vow will not take effect).
Inference: R. Eliezer holds that the vow does not take effect.