Bava Batra 11 - Partners Divide Properties
Partners may not divide a jointly owned courtyard against the will of one of them - unless there are four amot left in the courtyard for each, which is an area of about six feet by six feet. In addition, there must be four amot in front of each one's door, for unloading animals.
The general rule is: anything that after division retains its name (such as a cloak if after division it becomes two small cloaks, and not two pieces of a garment) may be forcibly divided. However, partners may not divide scrolls of the Holy Scripture, even if both agree to it, since cutting them in court would be a disgraceful act.