Subclass, subproperty, identity by inverse-functional properties, and owl:sameAs are processed at run time if an inference context option is specified in the query.

There is a general-purpose transitivity feature that can be used for a wide variety of graph algorithms. For example:

SELECT ?friend
WHERE
  {
    <alice> foaf:knows ?friend option (transitive)
  }

would return all the people directly or indirectly known by <alice>.