744. Paths From Public Domains to Alleys

Shabbos 17:18

Let’s say that an alley opens completely to a courtyard that opens to a public domain on the other side. In such a case, it is prohibited to carry in the alley because it is like an open alley (enclosed on only two sides). It is permitted to carry in the courtyard because, even though many people pass through a courtyard by entering on one side and exiting on the other, it is still a private domain.

Shabbos 17:19

If several paths lead from a public domain to an alley, connecting with it at different points, even though the entrances are not opposite one another, each one is considered an open alley because all of them lead to the public domain. In order to enable carrying in this alley, one must erect an entry frame for each of these paths at one end. Similarly, an entry frame must be erected at the alley’s main entrance. The other end of each path requires either a vertical pole or a horizontal beam.