Answer: Regarding his wife's vows, we do not distinguish between b'Rabim and Al Da'as Rabim. Since Rav Huna holds that b'Rabim it can be annulled, the same applies to Al Da'as Rabim for his wife's vows.

Implied question: [The Gemara] there challenged Rav Huna - he should be concerned lest she go to a Chacham, and he will permit her, and it answers that he holds that one must detail the vow;

It could have answered that he imposes a vow on her Al Da'as Rabim!

Answer #1: It did not need [to give that answer].

Answer #2: Rav Huna argues with Ameimar. What Ameimar said "even the one who says that a vow b'Rabim can be annulled" - he does not refer to the argument of Amora'im, i.e. Rav Huna and Rav Nachman in Gitin (35b). (If Ameimar came to teach about Rav Huna's opinion, it would not help to answer that Rav Huna argues, for still it is difficult for how Ameimar understood Rav Huna!);

Rather, [he refers to] the argument of Tana'im, of R. Yehudah and Rabanan, in Gitin (46a).

Citation: In Gitin (36a) the text says [like here] "the Halachah is, even according to the opinion...", and in Makos (16a) the text in most Seforim says "the Halachah is, a Neder vowed b'Rabim can be annulled, and Al Da'as Rabim cannot be annulled."

Pesak: According to [the latter] text, it connotes that this is the Halachah, that a Neder vowed b'Rabim can be annulled;

And even according to Seforim in which the text says "even according to the opinion that a Neder vowed b'Rabim...", that he does not come now to rule about a vow b'Rabim, even so we can infer from his need to rule that Al Da'as Rabim cannot be annulled according to everyone, that he holds that b'Rabim it can be annulled;

If it could not be annulled, all the more so Al Da'as Rabim. He should have said without the expression of a ruling (i.e. "the Halachah is") "even according to the opinion..."!

Implied question: We conclude in Gitin (35b) that according to Rav Nachman, we impose a vow on her b'Rabim. This implies that we hold like this (that this helps, for it cannot be annulled), for we hold like him in Dinim (monetary laws), and it was asked regarding Dinim!

Answer: [The Gemara] asks afterwards (36a) "this is fine for the opinion...", and it does not refer only to the Mishnah of our Perek brought there. Rather, it refers also to Rav Nachman. (Tzon Kodoshim - Rav Nachman answered "we impose... b'Rabim" for Rav Huna, but Rav Nachman himself holds that b'Rabim it can be annulled.)

Support (for Pesak): And also, since Rav Acha imposed a vow on the teacher of children Al Da'as Rabim, this implies that he holds that b'Rabim it can be annulled;

It is unreasonable to say that the reason he needed Al Da'as Rabim, and did not say "impose a vow on him b'Rabim", because there were not Rabim available in front of him.

Implied question: Rav Yosef said in Pesachim (107a) "I will vow b'Rabim that I will not drink beer." This implies that he holds that b'Rabim it cannot be annulled!

Answer: We do not hold like this.

Explanation (R. Tam): This is because presumably, the Rabim that the vow was made on their Da'as are pleased [to allow Hafarah for a Mitzvah].

Explanation (R. Tam): Al Da'as Rabim is when he specifies "Al Da'as Ploni and Ploni and Ploni", and even not in front of them. However, "Al Da'as Rabim" Stam has no effect;

And Al Da'as an individual or two people, even if he specified their names, a Chacham can permit without their consent.

Observation: Here [the Mishnah first] explains the matter it began with. Sometimes it explains [first] the last matter mentioned, like it explains in Nedarim (2b).

Reference: In Nidah (26a) it explains, why was Sandal was taught in [our] Mishnah in Bechoros? It is for the child that comes after it [to teach that it is a Bechor only for inheritance].

Question: What is the Chidush [of the Gemara's answer]? It is explicitly taught so here [in our Mishnah]!

Answer: One might have thought that "the child that comes after it" is one that is born in another pregnancy, but not the one with the Sandal, for it is common that it is born before the Sandal (it does not "come after it");

Therefore, it asks, for which Halachah was this taught? I already know [a son from a later pregnancy is not a Bechor for Kohen], for it is after the one born with the Sandal, for there is no Sandal without a fetus!

It explains for that fetus itself born with the Sandal, it needed to teach, for sometimes it comes after the Sandal.

Explanation (Rashi): Most of the limbs are cut. They exempt the womb. However, the head does not exempt if it is cut.

Remark: Amora'im argue about this in Nidah (29a). R. Yochanan holds that even if the head was cut, it exempts.

Explanation #1 (Rashi): Her husband [converted] with her, and she gave birth. That child is a Bechor for a Kohen, for he is Peter Rechem in Yisrael, but not for inheritance, for his conception was not in Kedushah, and he does not inherit, for the Torah was Mafkir the semen of a Nochri - "v'Zirmas Susim Zirmasam."

Objection (and Explanation #2): There was no reason to explain this reason, for even without it, he does not inherit, for one who converted is like a newborn baby, and he is not considered [the baby's] father;

While he is still a Nochri, he is considered his father for inheritance, and we do not say that the Torah was Mafkir his semen for this, for a Nochri inherits his father mid'Oraisa!

Question: In Yevamos (98a) we say that Rabanan taught that a Nochri has no father - it is not because they wantonly have relations, and [the father] is not known, for two twins [come from] one drop of semen that split into two, and it teaches that they are not liable for Eshes Ach. This teaches that the Torah was Mafkir his semen for this, for a Nochri inherits his father mid'Oraisa - "v'Zirmas Susim Zirmasam."

It needs the reason that [the Torah] was Mafkir it, even though they converted, and the reason "he is like a newborn baby" does not suffice. This is astounding!

Answer: If not for the reason that [the Torah] was Mafkir his seed, we should forbid [the brothers] to marry each other's wives (after they are widowed or divorced), lest they be confused with Yisrael (and Yisraelim will come to marry their brothers' wives). There it connotes that there is no Isur, and "they are not liable" is not precise;

Also, we should have obligated Chalitzah, and there it teaches "they do not do Chalitzah or Yibum."

Implied question: He could have said that it mentioned his head due to this clause itself! It connotes that [this is only for] a Nefel, but a viable baby, the one after it is not a Bechor also for inheritance!

Answer: It is easier to infer from the Seifa.

Assertion: The Prozdor here, and in Chulin (68a) and in Shabbos (86b) are the same;

It is unlike in Nidah (42b), that from when the fetus stuck his head outside the Prozdor, he is considered born.

Proof: If here it discusses the Prozdor there, how can the Prozdor hurt, to impede [Halachic] birth, since the head is outside of it?!

Explanation: Rather, the Prozdor there is the outer room [of the womb], and the Prozdor here is the thickness of the thighs that cover the womb, which is between the thighs. One might have thought that it is not considered birth when the head leaves the womb [as long as it is between the thighs].

Implied question: Why does the Gemara use the same word, and the meaning is not the same?!

Answer: We find like this above (20a) that Tinuf (a dissolved fetus; alternatively, bubbles of blood) exempts from Bechorah, for it is considered a child, and it is unlike Tinuf in Nidah (29a), that most [animals] that who give birth secrete Tinuf (fluids, the day before giving birth).

Implied question: Why couldn't we challenge Shmuel from the Mishnah in Chulin (77a), that if the minority of a Shilya left [the womb before Shechitah], one may not eat it?

We infer from it there (68a) that exit of the head is birth, since we forbid when the minority left, lest the head was in that minority!

Answer: That is only for an animal, but we cannot learn from a person from there.

Implied question: The Seifa there (77a) taught "what is a sign of a child in a woman, so is a sign of a child in an animal"!

Answer: That refers to a Shilya, which is a sign of a child (but not how much must leave to be considered birth).

Implied question: In Chulin, how did we infer that exit of the head is birth? Perhaps it is forbidden because we decree the minority due to the majority, like it says in Bava Kama (11a)!

Answer: If exit of the head were not birth, it would not be proper to decree, since it is impossible to ever be considered birth through the minority.

Question: Since Shmuel was refuted, why does it say in Nidah (26a) regarding a Sandal "a fetus has life, therefore his head comes out, he is considered born. A Sandal is not [considered born] until its majority leaves"?

Even without the reason of life, even for dead Nefalim, the head exempts!

Answer #1: "Life" is not precise. Rather, it means proper to live;

Since it mentioned this expression there above "a fetus, which has life, clings [to the wall of the womb], and does not leave [first]. A Sandal, which has no life, is smooth, and comes out [first]", it mentioned this also afterwards.

Answer #2: Some Seforim there say "a fetus, which has life, once it majority leaves (he is considered born). A Sandal [is not considered born] until all of it leaves." We can explain that "majority" means the majority of the head;

Some texts explicitly say "once the majority of the head leaves."

Citation (Nidah 29a): In the Sugya of "if the fetus came out cut up or Mesuras (feet first)", from when the majority leaves it is considered born. This implies that if it came out properly, the head exempts. R. Yosi says, from when it comes out properly alive.

Explanation #1 (R. Chananel): "Alive" means viable.

Rejection: Even for Nefalim, the head exempts, for Shmuel was refuted here!

Explanation #2: Rather, it is like Rashi explained there. "Properly alive" means whole, to exclude cut up.

Question: What is the Chidush of this matter more than other matters for which it is considered like born, e.g. to obligate his brother's wife to do Yibum (or Chalitzah, i.e. if a man died without children, and his only brother is this baby), and to exempt from Yibum (if he was born before his father died), and one who kills him is Chayav [Misah], and other matters taught there in Nidah (43b)!

Answer: It needs to teach here, for one might have thought that even though exit of the head is considered birth, in any case birth of the rest of the body, which left in Kedushah, is likewise considered like birth, and she should get days of Tum'ah and days of Taharah.

Question: In Kidushin (78b) and in Bava Basra (127b, the Gemara) struggles [to explain] according to Rabanan of R. Yehudah, why it says Yakir. (R. Yehudah expounds that Yakir teaches that a father is believed to disqualify a son, e.g. by saying that he is not his Bechor.) It should say that Rabanan need it for like we expound here!

Implied suggestion: We did not, for R. Yochanan argues (he does not expound so).

Rejection: (He agrees.) He says "even for inheritance" because he holds that also the forehead is recognition!

Strengthening of question: Also in Bava Basra there (the Gemara) struggles according to R. Meir, who says that Adam Makneh [Davar she'Lo Ba l'Olam, why must the Torah teach that a man is believed to identify his Bechor? Even without this, he could be Makneh to him an extra portion of what he has and will acquire! It answers that] Yakir comes [to teach that he is believed even] for property that he will acquire when he is Goses (close to death. A Kinyan does not help for such property. Why didn't it say that Yakir teaches like here?)

Note: This is also in Kidushin! Why did Tosfos mention specifically in Bava Basra? Perhaps the words "b'Yesh Nochlin" should be deleted from Tosfos. Alternatively, in Tosfos' text in Kidushin, it did not ask according to R. Meir.

Answer: There, the expression "Yakir" is difficult to [the Makshan]. It connotes that the father's recognition has power.

Explanation #1 (Rashi): Recognition of their faces is their testimony. This shows that also the face is needed (the forehead alone does not suffice).

Objection: Here and in Yevamos (120a) it brings the verse regarding the Beraisa, and not regarding the Mishnah in Yevamos (120a) "we testify only about the face with the nose"!

Explanation #2: Regarding the forehead of the Beraisa, it brings the verse. "Hakaras Peneihem Ansah Bam" connotes that there is something in man that through it, we recognize the face, i.e. the forehead. [You cannot say that it is the nose,] for the nose is included in the face!

Support: And there in Yevamos, after this verse, it brings the episode of Aba bar Marsa, who owed money to the Exilarch's house. He used wax to stick remnants of garments on his forehead, and passed in front of them, and they did not recognize him.