Halakhah su Numeri 30:11

There are those who say the “ḥupah” is not (constituted by) “yiḥud”, rather (“ḥupah” is) only when the husband (to-be) brings her from her father’s house to his house for the sake of marriage, even if he has not had ‘yiḥud” with her, for behold, it is written: “If she made a vow in the house of her husband” (Numbers 30:11), the meaning is that at all times when she is in her husband’s house, she is under his authority³³ Should be understood conversely, that she is the responsibility of her father or her husband. (Rin) to the first Chapter of Ketubot). And thus taught the sages: she is always under the authority of the (her) father, until she enters under the authority of the (her) husband in marriage; consequently, the essence of marriage is her entering under the authority (entering the domain) of the husband.
The Rambam holds that it is true: (her) entering under his domain constitutes marriage, but only in conjunction with “yiḥud”, because generally when he brings her into his house, he has “yiḥud” with her. But also, the opinion agrees with the Rambam, that, on the road, the essence (of valid marriage) is the “yiḥud”, as apparent in Chapter 57. (Ketubot 12b: “our rabbis taught [in a Baraita]: ‘he took her to his house … and she had witnesses so that it [her going with him, i.e. “yiḥud”] would not be hidden.’ ” There is no contradiction between the Rambam and the Tosafot, indeed, he does not rely on them. On the contrary, because of how remarkable in his reasoning, we suspend [the other opinion]. And the Rambam, at the beginning of Chapter 12, does away with witnesses, as it will be explained, with the help of heaven, in Chapter 67.)