  We envision a publish/subscribe ontology system that is able to index
millions of user subscriptions and filter them against ontology data that
arrive in a streaming fashion. In this work, we propose a SPARQL extension
appropriate for a publish/subscribe setting; our extension builds on the
natural semantic graph matching of the language and supports the creation of
full-text subscriptions. Subsequently, we propose a main-memory subscription
indexing algorithm which performs both semantic and full-text matching at low
complexity and minimal filtering time. Thus, when ontology data are published
matching subscriptions are identified and notifications are forwarded to users.
