why notification, business rules, etc. are not inherited from the parent table?

Hi,

  I am new to the developer group and I extended the incident table,, and assumed the notification and business rules, etc would be inherited to the child table. But it seems not, not sure if I miss any thing here? For example, there is a notification to notify called "Incident opened for me", if submit a new case from incident table, it fires, but if I submit a new case from the child table with the same condition, it did not fire.

  Could any one help out or point some related documentations of what and/or how to make those objects inherited   from   parent to child table?

Thanks lot!

Jerry