1,054. The Property of Partners

Shvisas Yom Tov 5:19

Continuing the case in halacha 5:18, if the first borrower made an eiruv techumim 1,000 cubits to the east of the cloak and the second borrower made an eiruv 500 cubits to the west of the cloak, the first borrower may only move the cloak within the 1,500 cubits to the east of the cloak's location, which is the end of yom tov boundary for the second borrower, who made his eiruv to the west. When the second borrower takes the cloak, he may only move it within the 1,000 to the west of the cloak's location, which is the end of yom tov boundary for the first borrower, who made his eiruv to the east. Therefore, if one borrower made his eiruv 2,000 cubits to the east of the cloak and the other made his eiruv 2,000 to the west, it may not be moved at all.

Shvisas Yom Tov 5:20

Similarly, if a woman borrows water or salt to make dough or food, the yom tov boundary of the dough or the food is based on those of both women. If two people bought an animal as partners and slaughtered it on yom tov, the yom tov boundary of the meat reflects the boundary of both of them. However, if they bought a jug of wine together and divided it on yom tov, the yom tov boundary of each one’s portion represents that of its owner. The reason for this distinction is that since the rule of boundaries is rabbinic, the principle of retroactive selection applies. It is therefore considered as if the each person’s share was separated for him in the jug before yom tov rather than mixed together. This is not the case with an animal. Even if each person’s share were to be considered as if separated within the animal, each portion is nourished by the other person’s portion so long as the animal is alive. Therefore, all of the animal's limbs are considered intermingled with the portion of each partner. Accordingly, the yom tov boundary of the meat reflects both partners’ boundaries.