Learn ontology engineering from the ground up in Protege, using the classic Pizza.owl tutorial, and see how it connects to a modern framework for building executable semantic systems.

You know how to build classes in Protégé. But do you know when to attach meaning — and when to wait?Volume 4 of "Mastering Ontology Engineering" introduces SKDL: the Semantic Knowledge Development Lifecycle. Seven stages. One discipline. Zero guesswork.From Aristotle to Description Logic. From taxonomy to executable knowledge.This is where pizza -> philosophy — and philosophy -> engineering.

Turn a static class hierarchy into a real semantic graph: object properties, inverse properties, property characteristics, and domain and range, all hands-on in Protege.

The chapter that grew into its own book: existential and universal restrictions, the correct VegetarianPizza pattern, and how OWL restrictions become EKA governance.