Gittin 78A

שם לווי, אבל אית ליה שם לווי ⁠– אף על גב דלא גבוה עשרה, ואף על גב דלא הוי ארבע אמות.

a modifier, meaning that this board is not referred to by a unique name. But if it has a modifier, even though it is not 10 handbreadths higher than the courtyard, and even though the board did not have an area of 4 cubits, it is still considered to be a separate domain, and it would therefore not be an effective divorce.

אפילו הוא עמה במטה כו׳: אמר רבא: לא שנו אלא במטה שלו, אבל במטה שלה ⁠– מגורשת.

§ It was taught in the Mishnah that if he throws a bill of divorce to his wife while she is in his house, she is not divorced, even if the bill of divorce is with her in the bed, i.e., he throws it onto the bed in which she is sitting or lying. Rava says: They taught this only in a case where he throws the bill of divorce to her and it is with her in his bed. But if he throws the bill of divorce to her and it is with her in her bed, then she is divorced.

תניא נמי הכי, רבי אליעזר אומר: במטה שלו ⁠– אינה מגורשת, במטה שלה ⁠– מגורשת.

This is also taught in a baraita: R' Eliezer says: If he throws the bill of divorce to her when she is in his bed, she is not divorced; if he throws it to her when she is in her bed, she is divorced.

ובמטה שלה ⁠– מגורשת? כליו של לוקח ברשות מוכר הוא; שמעת מינה: כליו של לוקח ברשות מוכר ⁠– קנה לוקח?

The Talmud asks: And if he throws the bill of divorce to her in her bed, is she divorced? But the bed is like vessels of a buyer that are in the domain of the seller, since the bed that belongs to her is in the house of the husband. Can you conclude from here that even if the vessels of a buyer are in the domain of the seller, the buyer acquires anything that is deposited into his vessels? This issue is disputed elsewhere. Some hold that when a vessel of the buyer is in the domain of the seller, the vessel cannot serve to acquire an item on behalf of the buyer.