res.addHyperedgesInNode(oldNode.hyperedges);
addNewNode(res, noPrune); //this will update the HashMap, so that the oldNode is destroyed
} else {//merge new to old, does not trigger pruningItems
oldNode.addHyperedgesInNode(res.hyperedges);
}
} else { // first time item
this.chart.nAdded++; // however, this item may not be used in the future due to pruning in the hyper-graph
addNewNode(res, noPrune);