public void removeEdges(QueryVertex v1, QueryVertex v2) {
		List<QueryEdge> adj1 = this.edges.get(v1);
		for(Iterator<QueryEdge> it = adj1.iterator(); it.hasNext(); ) {
			QueryEdge e = it.next();
			if(e.getEndPoint().equals(v2))
				it.remove();
		}
		if(adj1.size() == 0) {
			this.edges.remove(v1);
		}
		
		List<QueryEdge> adj2 = this.edges.get(v2);
		for(Iterator<QueryEdge> it = adj2.iterator(); it.hasNext(); ) {
			QueryEdge e = it.next();
			if(e.getEndPoint().equals(v1))
				it.remove();
		}
		if(adj2.size() == 0) {
			this.edges.remove(v2);
		}
	}