# [DL] problem with negated roles of SROIQ

Thomas Schneider schneidt at cs.man.ac.uk
Mon Jul 19 13:31:50 CEST 2010

Hi Nurmamat,

when you say "negated role provided by SROIQ", you probably mean the
feature of negated role assertions? These are restricted to ABoxes,
i.e., you can say that a pair (a,b) of individuals is not connected
via a role R.

However, this does not seem sufficient to define your class A. I
believe there is no way to exactly define that class in SROIQ, but
depending on what you want to do with A, you can try some workarounds.
Since your definition of A is ambiguous -- do I assume correctly that
you want to express

A=\{x| *there exists a y such that* (x,y) \in \neg R \wedge y \in C
\}

and that $neg R$ refers to the set of all pairs of individuals that
are not in R? Then you could define a new role S to be disjoint to R,
which would imply that S is subsumed by $\neg R$. Now if you define
the class A' to be equivalent to $\exists S.C$, you would get that A'
is a subclass of A. Perhaps this already suffices for what you want to
express?

Cheers

Thomas

On 29 Jun 2010, at 18:20, Nurmamat Helil wrote:

> Hi:
>
> I am not very familiar with DL. now I have to represent a class
> $A=\{x|(x,y) \in \neg R \wedge y \in C \}$ using DL
> can I use negated role provided by SROIQ.
>
> --
> Nurmamat Helil
> Postdoctoral Candidate
> School of Computer Science and Engineering
> Chung-Ang University
> Seoul, 156-756, South Korea
> Email: nurmamat at gmail.com
> ---
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