What's mean 'fb' and 'b' in Jena rules //OWL, RDFS

Question

There is a Jena rules
I don't know prefix b and fb. What different things each OWL and RDFS files?

PS. download URL is https://jena.apache.org/download/index.cgi and click jena-2.11.1-source-release.zip (MD5, PGP)

rules dir -> jena-core/src/main/resources/etc

Answer 1

The *.rules files are files with rules used by all the different Jena reasoners.

See the comments in the headers of the files. For example for the owl-fb.rules file it is:

OWL rule set v0.3 This rule set is designed to implement owl(f)lite using the hybrid rule system (mixture of forward and backward chaining). It differs from earlier versions by more consistently sticking to instance reasoning by being design to work with the LP backward engine.

It includes an experimental forward version of the equality reasoning which not yet scalable.

So b stands for backward chaining, f for forward chaining, and fb for a combination of the two.