Map<Label,CmpVertex> targetRed = coregraph.transitionMatrix.get(currentPair.getR()),
targetBlue = coregraph.transitionMatrix.get(currentPair.getQ());
for(Entry<Label,CmpVertex> redEntry:targetRed.entrySet())
{
CmpVertex nextBlueState = targetBlue.get(redEntry.getKey());
if (nextBlueState != null)
{// both states can make a transition
if (!AbstractLearnerGraph.checkCompatible(redEntry.getValue(),nextBlueState,coregraph.pairCompatibility))
return -1;// incompatible states