MB4 252a: Acquiring Rights to a Jointly Owned Chatzeir - part 1 (382:14-16)

If someone acquires rights from an employee of the owner for an eruv chatzerot, it only works while the worker is still employed by the owner of the house.

For how long can the rental be?

Can the rights be acquired from soldiers, police officers, or a treasurer of the king? What about from a retired government worker or solider who receives a pension?

What if a Jew and non-Jew live in the same house do rights need to be acquired from the non-Jew? What if they have separate areas within the dwelling.