Eruvin 95A

קורה ארבעה מתיר בחורבה, ורב נחמן אמר רבה בר אבוה: קורה ארבעה מתיר במים, מני?

A cross beam 4 handbreadths wide renders carrying in a ruin that is breached into a public domain permitted, as the edge of the cross beam is considered to descend and seal the breach. And that which Rav Naḥman said that Rabba bar Avuh said: A cross beam 4 handbreadths wide renders carrying in water permitted like a partition. In accordance with whose opinion were these rulings stated?

להך לישנא דאמרת בעשר לא פליגי: בעשר, ודברי הכל. להך לישנא דאמרת בעשר פליגי: כרב.

The Talmud explains: According to this version that you stated, that Rav and Shmuel agree with regard to an opening no wider than 10 cubits, here it is referring to a cross beam that is no longer than 10 cubits, and everyone, both Rav and Shmuel, agrees with these rulings. According to that other version that you stated, that they disagree with regard to an opening no wider than 10 cubits, these rulings are in accordance with the opinion of Rav alone.

לימא אביי ורבא בפלוגתא דרב ושמואל קמיפלגי, דאיתמר: סיכך על גבי אכסדרה שיש לה פצימין ⁠— כשירה, אין לה פצימין, אביי אמר: כשירה, ורבא אמר: פסולה.

The Talmud suggests: Let us say that Abaye and Rava are disagreeing with regard to the point that was the subject of a dispute between Rav and Shmuel. As it was stated: If one placed roofing on top of a portico that has doorposts, i.e., pillars that form the beginnings of partitions, it is a valid sukka. If, however, he placed the roofing atop a portico that has no doorposts, there is a dispute. Abaye said: It is a valid sukka. And Rava said: It is invalid.

אביי אמר כשירה, אמר פי תקרה יורד וסותם. ורבא אמר פסולה, לא אמר פי תקרה יורד וסותם. לימא אביי כרב, ורבא כשמואל?

The Talmud elaborates: Abaye said: It is valid. As he said: The edge of a roof descends and seals. Since the portico is roofed, it is considered to have partitions as well. And Rava said: It is invalid, as he did not say: The edge of a roof descends and seals. Let us say that Abaye holds in accordance with the opinion of Rav, and Rava holds in accordance with the opinion of Shmuel?