return levelOff;
}
public void setIndexForPropositions(PropositionLevel propositionLevel){
for (Iterator<Proposition> it = propositionLevel.iterator(); it.hasNext();) {
Proposition p = it.next();
if(!this.propositions.contains(p)){
p.setIndex(propositionLevel.getIndex());
this.propositions.add(p);
} else p.setIndex(this.propositions.ceiling(p).getIndex());
}
}