How fast are RIF processors compared to RDFS inference and OWL inference?
Since RIF can often be implemented by translation to other rule languages, we can speculate that the performance will differ only by the time need for translation. Many RDFS and OWL systems use underlying rule engines to do their inference, so their performance is likely to be the same or better on RIF. On the other hand, there are some OWL inference tasks which can be much more efficiently handled by DL algorithms.
