What is the validity of selling a boundary-defined half share of a house, such as 'half of my house adjacent to your house'?

Chapter on Selling Assets and Fruits

Al-Mughni

Book of Sales

Book 12 · Issue 8 · Bab 4

Open in Qurani

Primary text

Selling half of a house defined by the boundary of the neighbor's property is invalid. This is specified because the extent of that half is unknown, thus rendering the subject matter ambiguous.