Eiruvin 6:4-5

Eiruvin 6:4

Beis Shammai say that someone can only renounce his rights in a courtyard before Shabbos begins; Beis Hillel say that it can even be done after Shabbos begins. If the one who renounced his rights carried into the courtyard, whether accidentally or on purpose, it is considered asserting his rights, so they are un-renounced and he impedes the other residents from carrying in the courtyard. This is the opinion of Rabbi Meir; Rabbi Yehuda says he only impedes the others if he carried in the courtyard intentionally.

Eiruvin 6:5

If residents of the same alleyway are business partners and they jointly own wine in a barrel, they need not make an eiruv. If one owns the wine and another owns oil, they must make an eiruv. Rabbi Shimon says that they need not make an eiruv in either case.