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Note in figure 4.18 the two classes listed under Disjoint With and highlighted in yellow. This is an 
example of an inference from the reasoner. When we defined Pizza, PizzaBase, and PizzaTopping 
we made those 3 classes disjoint. I.e., no individual can be a member of more than one of those classes. 
Since MargheritaPizza is a subclass of Pizza it is also disjoint with PizzaBase and 
PizzaTopping, so the reasoner has added this information to the definition of MargheritaPizza and 
as with all inferences from the reasoner highlighted the new information in yellow.  
We will now create the class to represent an AmericanaPizza, which has toppings of pepperoni, 
mozzarella and tomato. Because the class AmericanaPizza is similar to the class MargheritaPizza 
(i.e., an AmericanaPizza is almost the same as a MargheritaPizza but with an extra topping of 
pepperoni) we will make a clone of the MargheritaPizza class and then add an extra restriction to say 
that it has a topping of pepperoni. 
Exercise 16: Create AmericanaPizza by Cloning MargheritaPizza and Adding Additional 
Restrictions 
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1. Select MargheritaPizza from the class hierarchy on the Classes tab.    
2. Select Edit>Duplicate selected class. This will bring up a dialogue for you to duplicate the class. The 
default is the name of the existing class so there will be a red error message when you start because you 
need to enter a new name. Change the name from MargheritaPizza to AmericanaPizza. Leave all the other 
options as they are and then select OK.  
3. Make sure that AmericanaPizza is still selected. Click on the Add icon (+) next to the SubClass Of field 
in the Description view for AmericanaPizza.    
4. Use either the Object restriction creator tab or the Class expression editor tab to add the additional 
restriction: hasTopping some PepperoniTopping.  
5. Click on OK to enter the new restriction.   
6. Edit the comment annotation on AmericanaPizza. It should currently be: A pizza that only has 
Mozzarella and Tomato toppings since it was copied over from MargheritaPizza. Note that at the top 
right of the comment there are three little icons, an @ sign, an X and an O. Click on the O. This icon is 
the one you use to edit any existing data in Protégé. This should bring up a window where you can edit 
the comment. Change it to something appropriate such as: A pizza that only has Mozzarella, Tomato, and 
Pepperoni toppings. Then click on OK to enter the edit to the comment. 
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Exercise 17: Create AmericanaHotPizza and SohoPizza 
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1. An AmericanaHotPizza is almost the same as an AmericanaPizza but has Jalapeno peppers on it. 
Create this by cloning the class AmericanaPizza and adding an existential restriction along the 
hasTopping property with a filler of JalapenoPepperTopping.