|  David wrote: I want to get all items that have a property with values from A, but not from B.
|
|  That appears to be problematic in OWL, but here's how to do it in Executable English / Internet business Logic


an-item has a property with a value belonging to A
not : that-item has a property with a value belonging to B
--------------------------------------------------------------------------------
that-item has a property with value(s) from A but no property with values from B


an-item has a property with the value a-val
that-val belongs to a-group
-------------------------------------------------------------
that-item has a property with a value belonging to that-group


this-value belongs to this-group
================================
   v1                     A
   v2                     A
   v2                     B


this-item has a property with the value this-val
================================================
  item1                                 v1
  item1                                 v2
  item2                                 v1


| This file is an application written in the language Executable English.
| You can view, run and change it by pointing a browser
| to www.reengineeringllc.com and selecting OwlSetDifference .