Lesson 304

Knowledge Graphs & the Semantic Web

RDF · ontologies · SPARQL · linked data

1:00

How facts are stored as subject–predicate–object triples, linked by URIs into a queryable, reasoning-capable graph — and how embeddings predict the links that are missing.

By the end, you can

  • Identify the subject, predicate, and object in any triple and explain how multiple triples form a graph.
  • Read Turtle notation and explain what a namespace prefix does.
  • Distinguish TBox (ontology/schema) from ABox (instance data) and explain why both are stored as triples.
  • Trace a simple inference step (subclass transitivity) and explain why the derived fact was never written down.
  • Write and interpret a basic SPARQL SELECT query with triple patterns and variables.
  • Explain the TransE equation h + r ≈ t and describe how it supports link prediction.
  • Name three real-world knowledge graphs and their key characteristics.
  • Explain how grounding an LLM on a knowledge graph reduces hallucination and enables multi-hop reasoning.
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