knowledgeDfNotUsed.retainAll(knowledgeDfNotUsedInKB); Set<Query> undefinedBeliefQueries = this.program.getKRInterface().getUndefined(tempDbfs, getBeliefQueries()); Set<Query> unachievableGoals = this.program.getKRInterface().getUndefined(tempDbfs, getGoals()); Set<Query> undefinedGoalQueries = this.program.getKRInterface().getUndefined(tempDbfs, getGoalQueries()); .removeAll(this.program.getKRInterface().getUndefined(getKnowledge(), new LinkedHashSet<Query>(0)));