Hi, I get an error with the following rule that appears only when I use the not keyword. If I remove the not keyword, it seems ok: rule "WCDMA->GSM Bidirectional Relations Evaluation Rule - Version 4" salience 10 dialect "java"         when                 $extgsmcell : ExternalGsmCell()                 $utrancell : UtranCell() from $extgsmcell.getIncomingUtranCells($extgsmcell.fdn)                 $extutrancell : ExternalUtranCell ( rncid==$utrancell.rncid, cellid==$utrancell.cellid )                 not GsmCell( lac==$extgsmcell.lac, cellid==$extgsmcell.cellid) from $extutrancell.getIncomingGsmCells($extutrancell.fdn)         then                 System.out.println("Version 3: Missing Cell Relation from " + $utrancell.getFdn() + " to " + $extgsmcell.getFdn()); End Any suggestions? Thanks, Ryan. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users