45 
 
property called hasSpiciness with only a few possible values ranging from Mild to Hot.  In this 
section we will also create the first individuals in our ontology.  
Exercise 24: Create an Enumerated Class to Represent the Spiciness of a Pizza 
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1. Create a new subclass of owl:Thing called Spiciness.   
2. Make sure that Spiciness is selected. Click on the Add icon (+) next to the Instances field in the 
Description view. 
3. You will be prompted with a window that looks like figure 4.24. The diamond icon at the top is for 
creating a new individual. The circle with an X through it is for deleting an individual. Use the diamond 
icon to create 3 individuals: Hot, Medium, and Mild, so your UI looks like figure 4.24, then click on OK.  
4. You may notice that only one of the new individuals was actually created as an instance of 
Spiciness. That’s okay. The next step will supply the reasoner with enough information to make the 
other two also be instances of Spiciness. 
5. Make sure that Spiciness is still selected. Click on the Add icon (+) next to the Equivalent To field in 
the Description view. This time we will create a defined class by directly entering the definition for the 
class into this field. Select the Class expression editor tab and enter the DL axiom: {Hot, Medium, Mild}. 
Select OK.  
6. Now run the reasoner. You should see that Spiciness is now a defined class and all three individuals: 
Hot, Medium, and Mild, are now instances of that class.  
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Figure 4.24 Creating Individuals for an Enumerated Class 
 
 
4.15 Adding Spiciness as a Property  
Next we need to add a property that will define the spiciness of a PizzaTopping.