public Corner (Vertex v)
		{
			this.vertex = v;
			edges = new List<HighLevelEdge> ();
		}
		public Edge (Vertex v1, Vertex v2) {
			this.v1 = v1;
			this.v2 = v2;
			this.faces = new List<Face> ();
			this.parent = null;
		}
		public int indexOfVertex(Vertex v) {
			return vertices.IndexOf(v);
		}
		public bool contains(Vertex v) {
			return vertices.Contains(v);
		}
		public void addVertex(Vertex v) {
			if (!vertices.Contains(v))
				this.vertices.Add (v);
		}
		public void removVertex(Vertex v) {
			this.vertices.Remove (v);
		}
		public void addVertex (Vertex v) {
			vertices.Add (v);
		}