Yerushalmi Eruvin 9:5 ירושלמי עירובין ט׳:ה׳

MISHNAH: If somebody builds an upper floor connecting two houses⁸The houses are on two different sides of the public road; the construction creates a bridge between the sides. Since the outer walls of this bridge are at least 10 hand-breadths high, in R. Jehudah’s opinion they constitute acceptable partitions which turn the space between them into a private domain. In the opinion of the anonymous majority, no part of a public road may be made private., and similarly open bridges⁹A bridge open to the public as part of a public road. It is assumed that the railings at the sides of the bridge are 10 hand-breadths high and can act as partitions between the space under the bridge and the outside., one carries under them, the words of Rebbi Jehudah, but the Sages forbid it¹⁰Since the formulation is “prohibited” but not “he is liable”, the argument of R. Jehudah is accepted in principle but rejected rabbinically.. In addition, Rebbi Jehudah said that one may make an eruv for open alleys but the Sages forbid it¹¹If an alley is not a dead end it is a thoroughfare even if it cannot be used for vehicular traffic..

HALAKHAH: Paragraph⁶⁸Discussion of Mishnah 5.. Rav Huna said, no public domain⁶⁹For the rules of the Sabbath, not in other respects. Babli Šabbat 98a. is roofed. Rebbi Simeon bar Carsana said, did you not learn from the desert, and was the desert not roofed⁷⁰As the Babli loc. cit. explains, all rules of the Sabbath are derived from the Tabernacle in the desert, and the space under the carts used by the Levites to transport the disassembled Tabernacle was roofed public domain.? Our Mishnah does not say so, but “and similarly open bridges, one carries under them the words of Rebbi Jehudah, but the Sages forbid it.” It only says “but the Sages forbid it;” therefore there is no liability of a purification offering⁷¹Since “forbidden”, in contrast to “liable”, in talmudic terminology means “rabbinically, not biblically, forbidden.”.

Does it need a partition⁷²Following R. Jehudah, is the space under a bridge automatically private domain? The roadway represents a roof; does one say that the borders of the roadway define imaginary walls (as stated in Chapter 1, Notes 40,42), or does the definition of private domain imply the existence of actual walls (which seems to be implied by Šabbat 16, Note 84)?? Rebbi Abba said, it needs a partition. Rebbi Yose said, it does not need a partition. The colleagues said before Rebbi Yose, does Rebbi Abba not say it correctly? As we have stated⁷³Mishnah 8:7., “Rebbi Jehudah says, a partition should not be more than the wall between them.” He said to them, there⁷⁴In the case of the Mishnah here, where the roadway is a roof., where there is a roof, it does not need a partition. But here, where there is no roof, it needs a partition, as Rav Jehudah said, if it is open to an agricultural area⁷⁵He notes that R. Jehudah considers the area under the bridge as automatic private domain only if that domain is bordered by karmelit; if it were bordered by public domain in the biblical sense, even R. Jehudah would require actual partitions (standing or hanging.), but if it is open to the public domain it is forbidden if there are no partitions, but if there is a partition it is permitted.