This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
From earlier discussion among working group members on restriction/subsumption, there seem to be cases where R is derived from B by restriction but there are instances allowed by R but not by B. As a concerete example, please see bug 2205 (http://www.w3.org/Bugs/Public/show_bug.cgi?id=2205)
On 20 October 2006, the WG agreed to close this issue without change to the spec. The rationale given was that (given an appropriate definition of subsumption in line with the agreed behavior regarding element declarations, value constraints, etc.) yes, restriction should entail subsumption, and examples like that cited in bug 2205 are correctly handled (flagged as errors) by the current text of the spec.