957. Forgetting to Join the Shittuf

Eiruvin 5:11

If one of the residents of an alley goes away for Shabbos, he does not impede the other residents’ ability to carry (i.e., his ownership of a residence is not an impediment in his absence). Similarly, if one of the residents of an alley erects a pillar four or more handbreadths wide (at least a foot wide) in front of his entrance, he does not impede the ability to carry because he has put himself apart from the others and made his domain a separate entity.

Eiruvin 5:12

If the residents of an alley joined together in a shittuf but some of them forgot and did not participate, then those who forgot should forgo ownership rights of their properties in favor of those who made the shittuf. The laws of forgoing ownership rights are the same as forgoing ownership rights in a domain when one or more residents of a courtyard forgot to join an eiruv (see Hilchos Eiruvin 2:1-5). As explained previously (4:1), a person and the members of his household who rely upon him for meals are all considered as one when it comes to making an eiruv for a courtyard or a shittuf for an alley.