[DL] Question on DL negation

Matt Williams matthew.williams at cancer.org.uk
Mon Mar 5 11:45:22 CET 2007

Dear All,

As I understand, most DL's do not allow for the negation of roles.

However, given a formula of the form R(x,y) (where R is some role), 
since this is equivalent to (R(x,y) & \top(y)) which could be negated as 
¬( R(x,y) & \top(y)), is it possible to effectively relax this 
constraint in some cases without affecting the logic?

I'm interested in rules that have a single role as the head, and 
negation of such heads would be useful...


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