Gittin 78B

וגט יוצא מארבע אמות שלו לארבע אמות שלה.

and the bill of divorce extends from his 4 cubits into her 4 cubits, meaning that part of the bill of divorce is in his 4 cubits, and part is in hers. Therefore, in this case there is uncertainty whether she is divorced or whether she is not divorced.

והא אגיד גביה! אלא רבה ורב יוסף דאמרי תרוייהו: הכא בשתי כיתי עדים עסקינן ⁠– אחת אומרת קרוב לו, ואחת אומרת קרוב לה.

The Talmud asks: But isn’t the bill of divorce still attached to him, since part of it is within his 4 cubits, and therefore it cannot be considered as if he gave her the bill of divorce completely? Rather, one should explain as Rabba and Rav Yosef both say: Here we are dealing with two groups of witnesses; one says that the bill of divorce fell closer to him, and one says that the bill of divorce fell closer to her. Therefore, the expression in the Mishnah, equally balanced, is referring not to distance but to opinions.

רבי יוחנן אומר: ״קרוב לה״ שנינו ⁠– אפילו מאה אמה; ו״קרוב לו״ שנינו ⁠– אפילו מאה אמה.

As opposed to Rav, who explained that in the Mishnah, the word closer meant within 4 cubits, R' Yoḥanan says: We learned that closer to her means that the bill of divorce was actually closer to her, even if it was 100 cubits away from her. And we learned that closer to him means that it was actually closer to him, even if it was 100 cubits away from him.

היכי דמי מחצה על מחצה? אמר רב שמן בר אבא, לדידי מיפרשא לה מיניה דרבי יוחנן: הוא יכול לשומרו והיא אינה יכולה לשומרו ⁠– זהו קרוב לו; היא יכולה לשומרו והוא אינו יכול לשומרו ⁠– זהו קרוב לה; שניהם יכולין לשומרו, שניהם אין יכולין ⁠– זהו מחצה על מחצה.

The Talmud asks: According to the explanation offered by R' Yoḥanan, what are the circumstances of when it was equally balanced? Rav Shemen bar Abba said: This was explained to me personally by R' Yoḥanan himself: If it is so positioned that he can guard it and she cannot guard it, this is considered closer to him. If it is so positioned that she can guard it and he cannot guard it, this is considered closer to her. If it is so positioned that the two of them can guard it, or the two of them cannot guard it, this is considered equally balanced.