Exactly what is the definition of a weak entity set? As far as I have read in Korth, it is some entity set which has a part or all of its primary key in another entity set(also known as the identifying or owner entity set in this case). Nowhere I have read or can conclude that - that part of its primary key which is in owner set, has to be the primary key of the owner set also!
But, what is often implied in Korth is exactly it. Can anyone explain?