Yerushalmi Eruvin 9:2 ירושלמי עירובין ט׳:ב׳

MISHNAH: If a large roof is adjacent to a small one⁴This follows the Sages in Mishnah 1. The situation is supposed to be the same as described in the second part of the Mishnah for courtyards: the larger extends beyond the smaller roof on both sides; if a person fromf the smaller house uses his roof to go to the larger roof, the smaller roof plays the role of entrance gate to the larger one. Therefore the dweller in the smaller house may use his own roof only if he made an eruv with the larger house., the large one is permitted but the small forbidden. If a large courtyard is open to a small one, the large one is permitted but the small forbidden since it acts as a door to the large one.

HALAKHAH: “If a large roof is adjacent to a small one⁴This follows the Sages in Mishnah 1. The situation is supposed to be the same as described in the second part of the Mishnah for courtyards: the larger extends beyond the smaller roof on both sides; if a person fromf the smaller house uses his roof to go to the larger roof, the smaller roof plays the role of entrance gate to the larger one. Therefore the dweller in the smaller house may use his own roof only if he made an eruv with the larger house., the large one is permitted but the small forbidden.” Our Mishnah [refers to] one roof only, but on another roof it is forbidden⁴⁰Following the Sages in Mishnah 1, even if the two roofs belong to the same owner, it only is permitted to carry from the large onto the small but not from the small onto the large (Chapter 2, Notes 48,91).. If it is not level, but if it is level it is permitted⁴¹The Mishnah may even be read as following R. Meïr, in case there is a step from the large roof down to the small.. Our Mishnah disagrees with Samuel: “If a large courtyard is open to a small one, the large one is permitted but the small forbidden.” Should one not be able to move there up to the place of the partitions⁴²Why is a person living in the smaller house not permitted to use his roof if he keeps his distance from the large roof?? The colleagues said before Rebbi Yose in the name of Rebbi Aḥiyya: What Samuel said, on this Sabbath itself⁴³It is not quite clear which of Samuel’s statements the discussion refers to. It seems that one reads in the Mishnah the expression נפרצה as “was torn down” not as a prior state but that it was torn down on the Sabbath and Samuel holds (Chapter 6, Notes 158ff.) that what was permitted at the start of the Sabbath remains so for the entire Sabbath., what the Mishnah deals with the next Sabbath. Where do we hold? If they made one eruv together, they should be permitted both on this and on the next Sabbath. If they did not make any eruv, they should be forbidden both on this and on the next Sabbath. The case happened as it happened⁴⁴Chapter 8, Note 89.. Rebbi Abun bar Cahana said before Rebbi La: When each of them made separate eruvin, nevertheless the large one is permitted since it is breached along its entire length and the small one is forbidden since it was not breached along its entire length⁴⁵It seems clear that one has to switch the places of “breached” and “not breached.”.