Can anyone please answer my question regarding EER (Enhanced Entity Relationship Modelling). We know that there is a subclass in EER called 'Category'. It is the union of two or more superclasses. My question is, how do you show a 'Category' subclass and the related relationships using UML. I know it can be done in Crows Feet notation by putting a 'U' symbol inside a circle. But how do you represent it in UML. Thanks.