When you install Virtuoso, its highly scalable reasoning and inference capabilities may not be obvious.
Typical cases involve using
rdfs:subClassOf predicates in queries, and wondering why reasoning hasn't occurred in line with the semantics defined in RDF Schema.
The same can occur when using more sophisticated OWL predicates such as
Virtuoso's inference rule processing is implemented in a loosely coupled manner, allowing users to conditionally apply inference context (via rules) to SPARQL queries.
These rules must generally be created as described in the product docs.
The Virtuoso Faceted Browser VAD package delivers a shortcut to setting up and exploring RDF Schema and OWL reasoning.