The frame syntax of the Rule Interchange Format Basic Logic Dialect (RIF BLD) standardized by the World Wide Web Consortium is based on F-logic; RIF BLD however omits non-monotonic reasoning features of F-logic.
Also, F-logic is generally undecidable,[citation needed] whereas the SHOIN description logic that Web Ontology Language (OWL) DL is based on is decidable.
[5] A follow-up paper[6] from 1992 won the 2002 Test of Time Award from ACM SIGMOD.
[5] Classes and individuals may be defined in F-logic as follows: This states, that "men and women are persons" and that "Brad is a man", and "Angelina is a woman".
In particular, variables became prefixed with a ?-mark, the distinction between functional and multi-valued properties was dropped and replaced by cardinality constraints, plus other important changes.