Tohoros 6:10-7:1

Tohoros 6:10

A colonnade (a hall composed or roofed columns) is a private domain vis-à-vis the laws of Shabbos and a public domain vis-à-vis the laws of ritual impurity. A courtyard that many people enter through one door and exit through another is a private domain vis-à-vis the laws of Shabbos and a public domain vis-à-vis the laws of ritual impurity.

Tohoros 7:1

If a potter left his pots in the public domain and went down to drink, the pots nearest the wall remain clean but the pots adjacent to the street are unclean. Rabbi Yosi says that this is only the case when the pots aren’t tied together but when they are tied together, all the pots remain clean. If a learned person gave his house key to an unlearned person, the house remains clean since he only gave it to him in order to watch the key (and not to enter the house).