weighted roles and distance in description logic

Morning all, i'm trying to encode preference values
using Description Logic. 
A preference is a triple (user, item, value), but it's
hard to encode "value" in a useful manner usign
description logics. Probably if use a logic without
datatypes this cannot be done. 

I think that this can be seen as an instance of
weighting roles stuff, for example to encode
assertions like 
"The distance between A and B is 13 Miles". I know
that there is some experiments to extends description
logic with numerical values(see ubiquitous computing),
but i would like to know if there is some experiments
to do that without extending description logics.

Sorry for my english,
thanks in advance,
Cristiano Longo




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