What share does an additional person acquire when they ask to be partnered into an item already purchased by one person?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
If someone purchases an item and a man says, 'Partner me in it,' and the purchaser replies, 'I have partnered you,' it implies a partnership in half, as the unconstrained term signifies equality (division by two).
Supporting text
If two persons jointly purchase a slave, and a third person asks them, 'Partner us in it,' and they reply, 'We have partnered you,' it is held that the third party acquires one-third. This is because partnership implies equality, which is only achieved by dividing the item into three equal shares among the three parties.