A more thorough explanation:

Definition: The rule against inalienability is a principle that states that property cannot be made nontransferable. It is also known as the rule against trusts of perpetual duration. This means that property cannot be tied up in a trust forever, and must be able to be transferred or sold at some point.

Examples:

• A wealthy individual creates a trust that states their property can never be sold or transferred to anyone else. This violates the rule against inalienability because it makes the property nontransferable.
• On the other hand, a trust that allows for the transfer of property after a certain amount of time has passed does not violate the rule against inalienability.

The examples illustrate how the rule against inalienability works. The first example shows how a trust that makes property nontransferable violates the rule, while the second example shows how a trust that allows for transfer after a certain amount of time does not violate the rule.