Gemara

(Shmuel): If a woman vowed not to eat either of two loaves, and she longs to eat one, but she has no desire for the other, since her husband can annul the vow regarding the loaf she wants, he can annul the entire vow.

(Rav Asi, citing R. Yochanan): He can annul only regarding the one she wants.

Question #1 (Mishnah): If a woman vowed to be a Nezirah, her husband annulled it, but she did not know and drank or became Teme'ah, she is not lashed.

If he can annul only the part that pains her, this is only the Isur of wine. If so, the Mishnah should teach that she is lashed if she eats grape pits or skins!

Answer (Rav Yosef): Nezirus cannot be partial (so it is totally annulled).

Question #2 (Mishnah): If a woman vowed to be a Nezirah, and became Teme'ah, and later her husband annulled her Nezirus, she brings Chatas ha'Of.

If Hafarah takes effect only on the part that is Inuy (affliction), perhaps this is only regarding wine. Refraining from Tum'ah is not Inuy!

Answer: Refraining from Tum'ah is also Inuy. (Since she cannot bury others, no one will bury her.)

87a (Mishnah): If a woman vowed 'figs and grapes are forbidden to me', and her husband annulled regarding figs, it is not annulled. He must annul the entire vow.

Our Mishnah is like R. Yishmael:

(Beraisa - R. Yishmael): If she said 'figs and grapes are forbidden to me', and he affirmed regarding figs, the entire vow is affirmed. If he annulled regarding figs, it is not annulled. He must annul the entire vow;

R. Akiva says, "Ishah Yekimenu v'Ishah Yeferenu" - just like partial Kiyum suffices, also partial Hafarah suffices.

R. Yishmael: (We read "Yekimenu" like Yakim Mimenu, he will affirm from (i.e. part of) it.) It does not say "He will annul Mimenu"!

R. Akiva equates Hafarah to Kiyum. Just like partial Kiyum affirms the whole vow, also regarding Hafarah.

(R. Chiya bar Aba): Chachamim disagree with R. Yishmael and R. Akiva, and equate Kiyum to Hafarah. Just like partial Hafarah annuls only part of the vow, also partial Kiyum.

Rishonim

The Rif brings the opinions of Shmuel and R. Yochanan and the Sugya on 87a-b.

Rambam (Hilchos Nedarim 12:6): If a woman vowed not to eat either of two loaves, and she longs to eat one, but she has no desire for the other, her husband can annul the vow only regarding the loaf she wants.

Rambam (13:10): If a woman forbade to herself figs and grapes in a vow or oath, whether she forbade the entire species, or 'these figs and grapes', if her husband affirmed regarding figs and annulled regarding grapes or vice-versa, what he affirmed is affirmed, and what he annulled is annulled. We do not say that a partially annulled vow is totally annulled, like we say regarding Hatarah.

(Rosh 11:3): The Rambam rules like Chachamim. I say that we follow the Stam Mishnah even if there is an argument in a Beraisa.

Ran (87b DH Aval): Chachamim say 'just like partial Hafarah works partially...' This connotes that all agree to this. However, the Tosefta (7:7) says that partial Hafarah does nothing. Rather, the correct text is like that of the Ramban (and Rosh), 'just like partial Hafarah does not annul...'

Radvaz (13:10): The Rambam ruled based on his text of the Gemara. He was not concerned for the Tosefta, for perhaps Chachamim did not teach it.

Rashba: Surely R. Akiva does not agree that partial Hafarah works! Rather, we find that sometimes a Tana (here, Chachamim) derives one law from another, even though his opponent disagrees about the law he learns from.

Rosh (1): Shmuel says that her husband can annul the entire vow because it is all one vow, and there is some Inuy even regarding the second loaf. If he did not annul regarding the second loaf, we do not say that since it was partially permitted, it is totally permitted. We say so only regarding Hataras Chacham, which makes the vow a mistake from the beginning. The Noder intended only for the entire vow. The Halachah follows R. Yochanan. The questions against him were answered.

Perush ha'Rosh (82b DH b'Achas): The case is, one loaf is clean, and the other is from coarse flour, and she normally does not eat such bread. Alternatively, they are the same; she has no other bread, and it is Inuy not to eat at all.

Poskim

Shulchan Aruch (YD 234:36): If a woman forbade to herself figs and grapes in a vow or oath, whether she forbade the entire species, or 'these figs and grapes', if her husband affirmed one part and annulled the other, what he affirmed is affirmed, and what he annulled is annulled. We do not say that a partially annulled vow is totally annulled like we say regarding Hatarah.

Beis Yosef (DH Nodrah): The Tur explains the Mishnah to say that partial Hafarah does not permit at all. The Rambam rules like Chachamim, who say that partial Kiyum or partial Hafarah takes effect on that part. Even though we follow a Stam Mishnah against an argument in a Beraisa, 'this is R. Yishmael's opinion, but Chachamim say...' connotes that we follow Chachamim. Chachamim say 'just like partial Hafarah works partially...' This connotes that R. Yishmael agrees. The Rambam must explain the Mishnah in this way.

Hagahos Tur ha'Shalem (65): The Beis Yosef did not say that the Tur must explain like this. Surely, the Tur had the Ramban's text of the Beraisa, which says 'just like partial Hafarah has no effect...'

Rema: Some argue and say that partial Kiyum affirms the entire vow, and partial Hafarah does nothing.

Shach (77): It seems that the Tur learned from the Rosh (11:1). I say that the Rosh said so only according to Shmuel, who says that he can annul the entire vow. According to R. Yochanan, if he annuls all that he can, this is like total Hafarah! The Ran (82b DH Rav) says so explicitly. 'He annuls the one she desires' connotes that he explicitly annuls only that one.

Shulchan Aruch (63): If a woman vowed not to eat either of two loaves, and she longs to eat one, but she has no desire for the other, and her husband annulled for both of them, the Hafarah takes effect only for the loaf she wants.

Beis Yosef (DH u'Mah she'Chosav v'Davka): According to the Rosh and Tur, this is only when he annulled Stam. If he explicitly annulled only part, even that part is not annulled.

Question: Why can't he annul the entire vow? He can annul a vow about a bad species that she never tasted!

Answer #1 (Beis Yosef DH u'Pirshu): There, she vowed only from a bad species, so he can annul it. Alternatively, there she vowed from the entire species; here, she vowed only from these loaves.

Answer #2 (Taz 51): 'Bad' refers to something that she desires to eat, but it is harmful. If she does not desire it, this is not Inuy Nefesh!